Author name code: carpenter
ADS astronomy entries on 2022-09-14
author:"Carpenter, Kenneth G." 
------------------------------------------------------------------------  

Title: Transmissive H2O Reconnaissance Sounder, TH2OR — A Compact
    Time-Domain Electromagnetic Instrument for Groundwater Detection
Authors: Nunes, D. C.; Grimm, R. E.; Barba, N.; Burgin, M.; Carpenter,
   K.; Krieger, S.; Manthena, R.; McGarey, P.
Bibcode: 2022LPICo2655.5054N
Altcode:
  We are developing a planetary low-power, low-mass transient
  electromagnetic sounding instrument intended to test the hypothesis
  of an extant deep global aquifer at Mars.

Title: VizieR Online Data Catalog: ASTRAL: abundance analysis of HR
    465 (Nielsen+, 2020)
Authors: Nielsen, K. E.; Carpenter, K. G.; Kober, G. V.; Wahlgren,
   G. M.
Bibcode: 2021yCat..18990166N
Altcode:
  The ASTRAL: Hot Stars Treasury Program was designed to achieve the
  ultimate combination of high spectral resolution and signal-to-noise
  over the far- and near-ultraviolet spectrum. The spectrum of HR465
  covers the wavelength interval between 1150 and 3047Å and is composed
  of 21 coadded and merged individual recordings. The spectral resolution
  shortward of 2334Å is R~30000; however, for wavelengths below 1600Å
  the spectrum is modeled with a lower value (R~25000) to achieve a
  better match to the observation. For wavelengths above 2350Å the
  spectral resolution is ~117000. <P />(2 data files).

Title: After All, Where is the Martian Ground Water? TH2OR Can Help
Authors: Nunes, D. C.; Grimm, R. E.; Barba, N.; Burgin, M.; Carpenter,
   K.; Krieger, S.; Manthena, R.; McGarey, P.
Bibcode: 2021LPICo2595.8020N
Altcode:
  The detection of groundwater at Mars continues to be
  elusive. Geoelectric analogs offer guidance on using of the transient
  electromagnetic method (TEM), implemented as the TH2OR instrument,
  to sound for deep groundwater at Mars.

Title: Exposing the Lyman-alpha Profiles of Low-Mass Stars
Authors: Peacock, Sarah; Barman, Travis Stuart; Carpenter, Kenneth
   G.; Hintz, Dominik; Loyd, R. O. Parke; Schneider, Adam; Shkolnik,
   Evgenya L.
Bibcode: 2021hst..prop16646P
Altcode:
  Characterizing potentially habitable planets around low mass stars
  is a key focus of current and upcoming missions such as JWST and
  TESS. This focus stresses the need for a comprehensive understanding
  of the radiation environments in which such planets reside. Low-mass
  stars are typically much more active than solar type stars and the
  proximity of their habitable zones can be one tenth the distance. The
  far-ultraviolet (FUV) radiation emitted by these stars has the
  potential to alter an orbiting planet's atmospheric photochemistry,
  while the extreme-ultraviolet (EUV) radiation can cause the loss
  of planetary atmospheres and surface volatiles. Ly-a emission at
  1216 A is the dominant radiation source for low mass stars at FUV
  wavelengths and is critical for informing stellar atmosphere models
  used to predict the EUV spectrum, but directly measuring a low-mass
  star's Ly-a emission is almost always impossible because of the
  contaminating effects of interstellar hydrogen. Using Gaia DR2,
  we have identified a unique sample of six low mass stars for which
  a complete and accurate measurement of their Ly-a line profile is
  possible due to their very large radial velocities. Stars with very
  large radial velocities (&gt;100 km/s) will have their Ly-a emission
  Doppler shifted away from contaminating sources allowing for the
  rare opportunity to measure intrinsic Ly-a emission. These proposed
  observations of this rare sample of stars will triple the number of
  stars with Ly-a emission measured in this way and will improve the
  accuracy of computed spectra for all low-mass stars across wavelengths
  that drive planetary atmospheric evolution.

Title: A New Look into K-giants' Chromospheres
Authors: Rau, Gioia; Peacock, Sarah; Carpenter, Kenneth G.
Bibcode: 2021RNAAS...5...73R
Altcode:
  We report the preliminary modeling of archival Center for High
  Angular Resolution Astronomy (CHARA)/Visible spEctroGraph and
  polArimeter interferometric data of a K-giant star using the PHOENIX
  atmosphere code. We find that our preparatory model that includes
  only the chromospheric contribution closely reproduces the observed
  infrared Ca II triplet line profiles of a test star: the K-giant,
  β Cet. This preliminary work requires the additional modeling of the
  wind contribution to improve the agreement with observations. We plan
  to perform a systematic study of K-giants chromospheric emission with
  multi-wavelength and multi-technique observations and modeling. Our
  plans include extending the modeling work to include the underlying
  wind component for a larger set of stars. Stellar Parameters and Images
  with a Cophased Array, the second-generation instrument at CHARA,
  will be the ideal instrument to perform such observations and reveal
  the chromospheric activity of K-giants.

Title: Adaptable Autonomous Ocean Access Through Erupting Conduits
Authors: Carpenter, K.; Cable, M. L.; Ono, M.; Kornfeld, R. P.
Bibcode: 2020AGUFMP044.0015C
Altcode:
  The EELS architecture is designed to carry the latest instruments. It
  is adaptable to traverse ocean world inspired terrain, fluidized media,
  enclosed labyrinthian environments and liquids. It is a snake-like
  self-propelled endoscope form comprising serially-replicated segments
  with encapsulated locomotion and bending. Multiple segments sequentially
  reverse rotations to reduce torsion, or replicate rotations to
  perform holonomic movements for steering. This is a first of its
  kind Archimedes screw propulsion configuration that act as wheels,
  tracks, gripping mechanisms, and propelling units under water working
  as propellers. These enable a robot to get to a plume and follow the
  streamline to its source and proceed into the open water. In the case
  of the unconsolidated plume ejected the robot is buoyant and propelled
  though the loose media by the threads, even up steep slopes and can
  burrow. In an open fracture system, EELS extends across the gap near
  the initiation point of a fracture out of the stream line and pushes
  the two end screw mechanisms on each side into the walls, driving
  into the plume, then descending. In the vent the threads bite the side
  walls, reacting the plume jet forces and creating forward movement when
  rotated. The robot stays on the edge of the vent pushing on the outer
  walls allowing the vent streamline to pass through the middle. Sensor
  feedback enables us to perform accurate force/compliance control without
  perfect knowledge of the geometry of the environment; hence the robot
  can naturally conform its shape to the size of the vent. This is used
  to move the drive screws in any direction to maintain a desired outward
  force on crack and vent walls, make the screw threads grip the surface,
  direct the robot around bends, and to follow the correct branch of a
  conduit across wide gaps. This potential concept has never before been
  realized. We will report on the latest developments of this concept
  and implications for unique ocean world science.

Title: The Advanced Spectral Library (ASTRAL): Abundance Analysis
    of the Chemically Peculiar Star HR 465
Authors: Nielsen, Krister E.; Carpenter, Kenneth G.; Kober, Gladys V.;
   Wahlgren, Glenn M.
Bibcode: 2020ApJ...899..166N
Altcode:
  This paper presents the results of the spectrum analysis of the
  B-type magnetic chemically peculiar star HR 465. HR 465 shows unusual
  abundance patterns that vary with a period of 21.5 yr. Our observations
  are recorded at φ = 0.45, 0.68, and 0.85 of the spectroscopic period,
  where φ = 0 represents the phase of maximum flux in the photometric
  y-band. Synthetic spectra, computed using an LTE atmosphere model,
  are fit to high-resolution ultraviolet Hubble Space Telescope (φ
  = 0.45) spectra obtained as part of the Advanced Spectral Library
  Project: Hot Stars program. The ultraviolet data are supplemented by
  high-resolution optical spectra (φ = 0.68 and 0.85) recorded at the
  Nordic Optical Telescope with the SOFIN spectrograph. The optical data
  are used as a complement to the high line-density ultraviolet spectrum
  to derive accurate abundances for elements without spectral lines in
  the ultraviolet and to improve the abundance phase coverage for many
  atoms/ions. This analysis presents abundance results for more than
  70 atoms/ions and confirms parts of the abundance characteristics
  previously reported where elements with high mass numbers show
  significant abundance enhancements compared with solar values while
  some of the lighter elements show abundance deficiencies. In addition,
  our measured abundances are consistent with the periodic variability for
  chromium and rare-earth elements. Our results are compared with earlier
  investigations of this peculiar object to constrain stellar abundance
  and diffusion. * Based on observations with the NASA/ESA Hubble Space
  Telescope obtained at the Space Telescope Science Institute, which is
  operated by the Association of Universities for Research in Astronomy,
  Inc., under NASA contract NAS5-26555.

Title: The Search for Liquid Water and Modern-Day Habitats in the
    Martian Subsurface
Authors: Stamenkovic, V.; Grimm, R. E.; Burgin, M. S.; Barba, N.;
   Manthena, R.; Carpenter, K.; Wright, D.; Krieger, S.; Arumugam, D.;
   Beauchamp, R.; Wilcox, B.; Edwards, C.
Bibcode: 2020LPI....51.1778S
Altcode:
  We show how transient electromagnetic sounding can be used to search for
  liquid groundwater and modern-day habitats in the martian subsurface.

Title: Stellar Imager (SI) — A UV/Optical Interferometer to Observe
    the Universe in High Definition
Authors: Carpenter, K. G.; Karovska, M.; Rau, G.; Schrijver, C.;
   SI Team
Bibcode: 2020AAS...23530102C
Altcode:
  The concept for a space based, UV/Optical Interferometer
  with over 200x HST's resolution, named "Stellar Imager" (<A
  href="http://hires.gsfc.nasa.gov/si/">http://hires.gsfc.nasa.gov/si/</A>),
  was developed as part of the NASA Vision Mission studies ("NASA
  Space Science Vision Missions" 2008, ed. M. Allen). SI was a
  "Landmark/Discovery Mission" in the 2005 Heliophysics Roadmap and a
  candidate UV-optical interferometer (UVOI) in the 2006 Astrophysics
  Strategic Plan. SI would enable 0.1 milli-arcsec spectral imaging of
  stellar surfaces, and many sources in the Universe in general, and open
  an enormous new "discovery space" for Astrophysics with its combination
  of high angular resolution, dynamic imaging, and spectral energy
  resolution. SI's goal is to study the role of magnetism in the Universe
  and revolutionize our understanding of: 1) Solar/Stellar Magnetic
  Activity and their impact on Space Weather, Planetary Climates, and
  Life; 2) Magnetic and Accretion Processes and their roles in the Origin
  and Evolution of Structure and in the Transport of Matter throughout
  the Universe; 3) the close-in structure of Active Galactic Nuclei;
  and 4) Exo-Solar Planet Transits and Disks. Significant technology
  development is critical to enabling SI and other future space-based,
  sparse aperture telescopes and distributed-spacecraft missions. The
  key technology needs include: 1) precision formation flying of many
  spacecraft, 2) precision metrology over km-scales, 3) closed-loop
  control of many-element, sparse optical arrays, 4) staged-control
  systems with very high dynamic ranges (nm to km-scale). We describe
  the needed technology development, science goals, and feasibility
  of interferometry from space, as well as provide detail performance
  parameters and simulations of the data that could be acquired by this
  space interferometer.

Title: Sailing the winds: exploring the mechanisms driving the winds
    in carbon-rich AGB Stars
Authors: Rau, G.; Ohnaka, K.; Wittkowski, M.; Carpenter, K.;
   Airapetian, V.
Bibcode: 2020AAS...23530101R
Altcode:
  Evolved stars produce molecules and dust in their extended atmospheres,
  enriching significantly the interstellar medium. To understand their
  mass loss, it is of fundamental importance to investigate the structure
  and atmospheric dynamics of these stars. V Oph, a carbon-rich Asymptotic
  Giant Branch (AGB) star, shows extended molecular layers, which vary
  over a time scales of tens of days. Our study aims at understanding
  if these variations can be explained by dust-driven winds triggered
  by stellar pulsation alone, or if other mechanisms are operating. We
  show our results, presented in a recent ApJ article, using our
  multi-technique modeling of existing photometric and interferometric
  VLTI/MIDI data using the latest generation DARWIN models for C-rich
  AGB stars. Our results include estimates of the values of fundamental
  stellar parameters and a comparison with evolutionary tracks. We also
  compute an alternative scenario for the mechanism that drive winds,
  based on Alfvén waves propagating in V Oph atmosphere. We found that
  the latter mechanism could partially contribute to the acceleration
  of the stellar winds of this star. Moreover, using period-luminosity
  sequences and interferometric modeling, we infer that V Oph could
  be reclassified to a semi-regular star. Future studies, such
  as observations with the new capabilities of the James Webb Space
  Telescope and with the second-generation instrument at the VLTI,
  MATISSE, will be discussed.

Title: AGB star atmospheres modeling as feedback to stellar
    evolutionary and galaxy models
Authors: Rau, Gioia; Wittkowski, M.; Chiavassa, A.; Carpenter, K.;
   Nielsen, K.; Airapetian, V. S.
Bibcode: 2019IAUS..343..491R
Altcode:
  The chemical enrichment of the Universe is considerably affected by
  the contribution of cool evolved stars. We studied the O-rich star
  R Peg and the C-rich star V Oph, using respectively the VLTI/GRAVITY
  and VLTI/MIDI instruments. We interpret the data using grids of 1-D
  and 3-D dynamic model atmospheres.

Title: The Impact of Dust/Gas Ratios on Chromospheric Activity in
    Red Giant and Supergiant Stars
Authors: Carpenter, Kenneth G.; Rau, Gioia
Bibcode: 2019IAUS..343..365C
Altcode:
  Stencel et al. (1986) analyzed IUE spectra of a modest set of cool
  stars and found that they continue to produce chromospheres even in
  the presence of high dust levels in their outer atmospheres. This
  reversed the previous results of Jennings (1973) and Jennings &amp;
  Dyck (1972). We describe an on-going extension of these studies to
  a sample of stars representing a broader range in dust/gas ratios,
  using archival IUE and archival and new HST data on both RGB and AGB
  stars. Surface fluxes in emission lines will be analyzed to assess
  the chromospheric activity and obscuration by dust in each star, as
  those fluxes will follow a different pattern for reduced activity
  (temperature/density dependent) vs. dust obscuration (wavelength
  dependent). Wind characteristics will be measured by modeling of
  wind-reversed chromospheric emission lines.

Title: Searching for Liquid Water in the Martian Deep with TH2OR
Authors: Burgin, M. S.; Stamenkovic, V.; Grimm, R. E.; Arumugam, D.;
   Beauchamp, R.; Barba, N.; Manthena, R.; Wright, D.; Wilcox, B. H.;
   Carpenter, K.; Edwards, C. D.
Bibcode: 2019AGUFM.P44B..02B
Altcode:
  The "holy grail" of planet exploration is the quest for life. This
  quest has been framed around "follow the (liquid) water", with
  the implication that seeking liquid water is tantamount to seeking
  habitable environments. For Mars, pure liquid water is generally only
  stable in the deep subsurface, at depths of kilometers. Here, we will
  describe (i) how we can use transient electromagnetic techniques (TEM)
  to sense liquid groundwater in the Martian subsurface and (ii) discuss
  the capabilities of the TH2 OR (Transient H2 O Reconnaissance) TEM
  instrument, which is currently being developed at JPL - with a targeted
  capability to detect liquid groundwater in the Martian subsurface down
  to depths of several kilometers while keeping payload mass and power
  small. Our TEM approach is different from radar soundings as it is not
  sensitive to the dielectric constant but rather to electric conductivity
  and allows much deeper penetration down to aquifer depths of ~1-10
  km due to the lower frequencies that are being used (~Hz-kHz for EM
  versus ~MHz for radar). EM exploits the fact that only slightly-saline
  water has an electric conductivity orders-of magnitude greater than
  dry rock. On Mars, we expect especially highly-saline waters due to the
  much longer residence time of groundwater than on the geologically and
  hydrologically much more active Earth. Moreover, as the Martian crust
  is expected to be much drier than the Earth's crust, we expect much
  greater contrast ratios in electric conductivity between overburden
  (crustal part above aquifer) and a putative aquifer on Mars than on the
  Earth. These "Martian TEM advantages" allow us to sound with TH2 OR
  down to depths of kilometers in order to infer the depth, thickness,
  and also salinity of liquid subsurface water. Salinity, especially in
  combination with information on local geothermal gradients, can hence
  also allow us to indirectly estimate its chemical composition. The
  ability to characterize the water chemistry to some degree is a
  particularly important feature of TEM sounding, which other methods
  generally lack. This opens the possibility to use TH2 OR to detect
  and characterize the habitability of deep subsurface environments on
  modern-day Mars.

Title: Exobiology Extant Life Surveyor (EELS)
Authors: Ono, M.; Carpenter, K.; Cable, M. L.; Wilcox, B. H.; Tosi,
   L. P.
Bibcode: 2019AGUFM.P21D3410O
Altcode:
  Exploring the depths of the Enceladus plume vents for liquid water,
  searching for life is one of the larger goals of current space
  exploration. Descending crevasses in ice sheets on Earth to discover
  the fate of melt water runoff and its effects are of Earth science
  interest. Finding a path to liquid water is the goal of any mission
  seeking extant life. We present a potential solution that is adaptable
  to the envelope of environmental parameters modeled. <P />The EELS
  architecture is designed to carry the latest instruments. It is
  adaptable to traverse ocean world inspired terrain, fluidized media,
  enclosed labyrinthian environments and liquids. It is a snake-like
  self-propelled endoscope form comprising serially-replicated segments
  with encapsulated locomotion and bending. Multiple segments sequentially
  reverse rotations to reduce torsion in the endoscope, or replicate
  rotations to perform holonomic movements for steering. The concept
  is a first of its kind Archimedes screw propulsion configuration that
  act as wheels, tracks, gripping mechanisms, and propelling units under
  water working as propellers. These enable a robot to get to a plume and
  follow the streamline to its source and proceed into the open water. In
  the case of the unconsolidated plume ejected the robot is buoyant and
  propelled though the loose media by the threads, even up steep slopes
  and can burrow. In an open fracture system, EELS extends across the
  gap near the initiation point of a fracture out of the stream line
  and pushes the two end screw mechanisms on each side into the walls,
  driving into the plume, then descending. In the vent the threads
  bite into the side walls, reacting the plume jet forces and creating
  forward movement when rotated. The robot stays on the outside of the
  vent pushing on the outer walls allowing the vent streamline to pass
  through the middle. The rotation of the screws is reacted by counter
  rotating secondary units which provide anchoring and thrust. In the
  case of wide caverns or slip of the leading screw unit, the additional
  Archimedes screw units provide grip until the leading units find
  their next secure position. Series elastic actuators enable us to
  perform accurate force/compliance control without perfect knowledge
  of the geometry of the environment; hence the robot can naturally
  conform its shape to the size of the vent. This is used to move the
  drive screws in any direction to maintain a desired outward force
  on crack and vent walls, make the screw threads grip the surface,
  direct the robot around bends, and to follow the correct branch of a
  conduit across wide gaps. This architecture has never been realized
  in any other robots to this point. It prioritizes reducing traversal
  time to the water gas interface in case of a primary battery only
  mission. Sensor arrays, cameras, and instruments at the head segment
  will provide in-situ feedback.

Title: Feasibility of a Mission to Enceladus' Subsurface Ocean for
    the Next Planetary Science Decadal Survey
Authors: Hofgartner, J. D.; Choukroun, M.; Cable, M. L.; Brophy, J. R.;
   Carpenter, K.; Polit Casillas, R.; Chmielewski, A. B.; Cooley, P.;
   Cutts, J. A.; Fleurial, J. P.; Landau, D.; Parness, A.; Reh, K. R.;
   Wilcox, B. H.
Bibcode: 2019AGUFM.P34C..06H
Altcode:
  Saturn's moon Enceladus is a high priority target for astrobiology as
  it harbors a subsurface ocean that erupts into space and is likely
  habitable. Searching for life at Enceladus is a top priority, near
  term goal of Ocean Worlds exploration (e.g., Hendrix et al., 2019,
  The NASA Roadmap to Ocean Worlds, and references therein). Several
  mission concepts to search for life in Enceladus' plume have been
  studied including proposed Discovery and New Frontiers missions. Is
  a mission that accesses the ocean and directly searches for life in
  unaltered ocean samples feasible in the coming decade? We present
  the results of an internal study at the Jet Propulsion Laboratory
  for an ambitious yet implementable mission concept to Enceladus'
  ocean. This innovative mission would include autonomous landing at
  Enceladus' south pole and penetration through the ice shell via both
  an intelligent melt probe and an adaptable multi-terrain robot (robotic
  eel) that navigates down an erupting vent. Both the eel and melt probe
  would be instrumented, able to search for evidence of life in samples
  acquired during their descent, and capable of maneuvering within the
  ocean. The baseline mission architecture would include a solar-powered
  orbiter to identify safe, compelling landing zones and relay data to
  Earth as well as an RTG-powered lander that would execute a precision
  landing, deploy the melt and eel probes, relay data to the orbiter,
  and also search for evidence of life in samples of surface material. A
  new surface sampling system has been developed to enable the latter
  search, based on experimentally-derived surface strength expectations
  (Hodyss et al., this meeting). The mission design would not be inhibited
  by winter darkness at Enceladus' south pole; all operations could be
  accomplished at any Enceladus season. The concept would utilize the
  state-of-the-art in astrodynamics techniques, systems architecture,
  optimization, and advanced manufacturing. A single Flagship-level
  mission that would search for life on Enceladus' surface, within its
  ice shell, and in the subsurface ocean may be the most comprehensive
  opportunity for astrobiology in the coming decade.

Title: Mobile Instruments for Mars Exploration (MIMEs) (Characterizing
    Recurring Slope Linea)
Authors: Carpenter, K.; Noell, A. C.; Christensen, L. E.; Zent, A.;
   Quinn, R. C.
Bibcode: 2019AGUFM.P44B..07C
Altcode:
  Definitive confirmation of current liquid water activity on Mars would
  be a major step in establishing the present day habitability of Mars
  and the possibility of extant life. The recurring slope lineae (RSL)
  are one of the most intriguing targets for exploring current water
  activity. <P />The RSL are identified as seasonally dependent streaks
  that darken and grow downward on steep (≥20°) slopes. Currently,
  they are best explained as intergranular briny water flows percolating
  through the top layers of the regolith, but orbital observations cannot
  provide a definitive confirmation. However, landing and probing near
  RSL presents a number of challenges to traditional mission architectures
  including stringent planetary protection requirements of a Mars special
  region mission. <P />To this we propose utilizing two versions of
  the Pop-Up Flat Folding Explorer Rover capable of traversing greater
  than 50 degree slopes and able to be cleaned to a greater then log 7
  reduction in bio burden. These will be equipped with the Thermal and
  Electrical Conductivity Probe (TECP) and/or a miniature version of
  the Tunable Laser Spectrometer (TLS) to characterize RSL and establish
  habitability. Having multiple PUFFER agents increases the communication
  range of the field survey by using individual PUFFERs as repeaters. <P
  />We will determine the permafrost freeze-thaw cycle that drives
  the underlying RSL processes at our field sites and characterize the
  chemical makeup of the flows. This will inform on the period of liquid
  phase and the available chemicals for biological processes. Overall,
  the MIME mission concept addresses fundamental NASA priorities of
  searching for life and habitable areas in our solar system. On Mars,
  present day habitability is still fundamentally tied to finding liquid
  water. <P />The Curiosity rover has provided abundant evidence of Mars
  habitability 3 - 4 billion years ago in the active lacustrine system
  of Gale Crater. MIME will pursue evidence for modern day liquid flows,
  and hence modern day habitability. A confirmed detection of liquid
  activity near the surface of Mars would intensify the already robust
  debate about the suitability of exploring Mars not only for signatures
  of past life, but also for signatures of extant life.

Title: Mars Subsurface Hydrology in 4D and Implications for Extant
    Life
Authors: Stamenkovic, V.; Plesa, A. C.; Breuer, D.; Burgin, M.;
   Grimm, R.; Arumugam, D.; Beauchamp, R.; Barba, N.; Manthena, R.;
   Wright, D.; Wilcox, B.; Carpenter, K.; Edwards, C.
Bibcode: 2019LPICo2108.5052S
Altcode:
  In this study, we show how ground-water levels might have evolved over
  the last 4.5 Ga inside the martian subsurface as a function of location,
  depth, and time using numerical geodynamical evolution models. We also
  show how to search for them.

Title: VizieR Online Data Catalog: ASTRAL: reference spectra for
    evolved M stars (Carpenter+, 2018)
Authors: Carpenter, K. G.; Nielsen, K. E.; Kober, G. V.; Ayres, T. R.;
   Wahlgren, G. M.; Rau, G.
Bibcode: 2019yCat..18690157C
Altcode:
  This paper focuses on the evolved cool stars γCru and αOri and
  compares their spectral characteristics to the well-studied K1.5III
  star αBoo (Hinkle+ 2005uaas.book.....H). The observational strategy
  for α Ori and γ Cru, as for the other objects in the ASTRAL Cool
  Star Program, was crafted to find the optimal combination of spectral
  resolution and signal-to-noise over the complete FUV and NUV spectra
  (1150-3159Å). <P />All of the HST Space Telescope Imaging Spectrograph
  (STIS) spectra for the two objects are splined in a top-level data set
  covering the entire wavelength region. An overview of the data used in
  this paper is presented in Table 1, and a more detailed description
  of the data, including the observing strategy, data reduction,
  coaddition, and splicing, can be found on the Advances Spectral
  Library (ASTRAL) website (http://casa.colorado.edu/~ayres/ASTRAL/)
  and at the Mikulski Archive for Space Telescopes (MAST)
  (http://archive.stsci.edu/prepds/astral/). <P />(4 data files).

Title: The Potential of Exozodiacal Disks Observations with the
    WFIRST Coronagraph Instrument
Authors: Mennesson, B.; Bailey, V.; Kasdin, J.; Trauger, J.; Absil,
   O.; Akeson, R.; Armus, L.; Baudino, J. L.; Baudoz, P.; Bellini,
   A.; Bennett, D.; Berriman, B.; Boccaletti, A.; Calchi-Novati, S.;
   Carpenter, K.; Chen, C.; Danchi, W.; Debes, J.; Defrere, D.; Ertel,
   S.; Frerking, M.; Gelino, C.; Girard, J.; Groff, T.; Kane, S.; Helou,
   G.; Kalirai, J.; Kral, Q.; Krist, J.; Kruk, J.; Hasegawa, Y.; Lagrange,
   A. M.; Laine, S.; Langlois, M.; Lowrance, P.; Maire, A. L.; Malhotra,
   S.; Mandell, A.; Marshall, P.; McElwain, M.; Meshkat, T.; Millan-Gabet,
   R.; Moustakas, L.; Nemati, B.; Paladini, R.; Postman, M.; Pueyo, L.;
   Quintana, E.; Ramirez, S.; Rhodes, J.; Riggs, A. J. E.; Rizzo, M.;
   Rouan, D.; Soummer, R.; Stapelfeldt, K.; Stark, C.; Turnbull, M.; van
   der Marel, R.; Vigan, A.; Ygouf, M.; Wyatt, M.; Zhao, F.; Zimmerman, N.
Bibcode: 2019arXiv190902161M
Altcode:
  The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument
  (CGI) will be the first high-performance stellar coronagraph using
  active wavefront control for deep starlight suppression in space,
  providing unprecedented levels of contrast, spatial resolution, and
  sensitivity for astronomical observations in the optical. One science
  case enabled by the CGI will be taking images and(R~50)spectra of
  faint interplanetary dust structures present in the habitable zone
  of nearby sunlike stars (~10 pc) and within the snow-line of more
  distant ones(~20pc), down to dust density levels commensurate with
  that of the solar system zodiacal cloud. Reaching contrast levels
  below~10-7 for the first time, CGI will cross an important threshold
  in debris disks physics, accessing disks with low enough optical
  depths that their structure is dominated by transport phenomena than
  collisions. Hence, CGI results will be crucial for determining how
  exozodiacal dust grains are produced and transported in low-density
  disks around mature stars. Additionally, CGI will be able to measure the
  brightness level and constrain the degree of asymmetry of exozodiacal
  clouds around individual nearby sunlike stars in the optical, at the
  ~10x solar zodiacal emission level. This information will be extremely
  valuable for optimizing the observational strategy of possible future
  exo-Earth direct imaging missions, especially those planning to operate
  at optical wavelengths, such as Habitable Exoplanet Observatory (HabEx)
  and the Large Ultraviolet/Optical/Infrared Surveyor (LUVOIR).

Title: Constraining Stellar Parameters and Atmospheric Dynamics of
    the Carbon AGB star V Oph
Authors: Rau, Gioia; Ohnaka, Keiichi; Wittkowski, Markus; Airapetian,
   Vladimir; Carpenter, Kenneth G.
Bibcode: 2019ApJ...882...37R
Altcode: 2019arXiv190708693R
  Molecules and dust produced by the atmospheres of cool evolved stars
  contribute to a significant amount of the total material found in the
  interstellar medium. To understand the mechanism behind the mass loss
  of these stars, it is of pivotal importance to investigate the structure
  and dynamics of their atmospheres. Our goal is to verify if the extended
  molecular and dust layers of the carbon-rich asymptotic giant branch
  (AGB) star V Oph, and their time variations, can be explained by
  dust-driven winds triggered by stellar pulsation alone, or if other
  mechanisms are in play. We model V Oph mid-infrared interferometric
  VLTI-MIDI data (8-13 μm), at phases 0.18, 0.49, and 0.65, together with
  literature photometric data, using the latest-generation self-consistent
  dynamic atmosphere models for carbon-rich stars: DARWIN. We determine
  the fundamental stellar parameters: T <SUB>eff</SUB> = 2600 K, L
  <SUB>bol</SUB> = 3585 L <SUB>⊙</SUB>, M = 1.5 M <SUB>⊙</SUB>,
  C/O = 1.35, \dot{M}=2.50× {10}<SUP>-6</SUP> M <SUB>⊙</SUB>
  yr<SUP>-1</SUP>. We calculate the stellar photospheric radii at the
  three phases: 479, 494, 448 R <SUB>⊙</SUB> and the dust radii: 780,
  853, 787 R <SUB>⊙</SUB>. The dynamic models can fairly explain
  the observed N-band visibility and spectra, although there is some
  discrepancy between the data and the models, which is discussed in the
  text. We discuss the possible causes of the temporal variations of the
  outer atmosphere, deriving an estimate of the magnetic field strength,
  and computing upper limits for the Alfvén waves velocity. In addition,
  using period-luminosity sequences, and interferometric modeling, we
  suggest V Oph as a candidate to be reclassified as a semi-regular star.

Title: Stars at High Spatial Resolution
Authors: Carpenter, Kenneth G.; van Belle, Gerard; Brown, Alexander;
   Cranmer, Steven R.; Drake, Jeremy; Dupree, Andrea K.; Creech-Eakman,
   Michelle; Evans, Nancy R.; Grady, Carol A.; Guinan, Edward F.; Harper,
   Graham; Karovska, Margarita; Kolenberg, Katrien; Labeyrie, Antoine;
   Linsky, Jeffrey; Peters, Geraldine J.; Rau, Gioia; Ridgway, Stephen;
   Roettenbacher, Rachael M.; Saar, Steven H.; Walter, Frederick M.;
   Wood, Brian
Bibcode: 2019arXiv190805665C
Altcode:
  We summarize some of the compelling new scientific opportunities
  for understanding stars and stellar systems that can be enabled by
  sub-milliarcsec (sub-mas) angular resolution, UV-Optical spectral
  imaging observations, which can reveal the details of the many dynamic
  processes (e.g., evolving magnetic fields, accretion, convection,
  shocks, pulsations, winds, and jets) that affect stellar formation,
  structure, and evolution. These observations can only be provided
  by long-baseline interferometers or sparse aperture telescopes in
  space, since the aperture diameters required are in excess of 500 m
  (a regime in which monolithic or segmented designs are not and will
  not be feasible) and since they require observations at wavelengths
  (UV) not accessible from the ground. Such observational capabilities
  would enable tremendous gains in our understanding of the individual
  stars and stellar systems that are the building blocks of our Universe
  and which serve as the hosts for life throughout the Cosmos.

Title: Understanding Component/Materials Performance in the Lunar
    Environment
Authors: Patterson, M. C. L.; Tucker, J.; Carpenter, K.; Parness, A.
Bibcode: 2019LPICo2152.5056P
Altcode:
  A test environment that closely approximates the lunar surface has
  been established to characterize the wear and degradation mechanisms
  associated with components such as gear boxes, predict performance,
  and establish mitigation strategies.

Title: Cool, evolved stars: results, challenges, and promises for
    the next decade
Authors: Rau, Gioia; Montez, Rodolfo, Jr.; Carpenter, Kenneth;
   Wittkowski, Markus; Bladh, Sara; Karovska, Margarita; Airapetian,
   Vladimir; Ayres, Tom; Boyer, Martha; Chiavassa, Andrea; Clayton,
   Geoffrey; Danchi, William; De Marco, Orsola; Dupree, Andrea K.;
   Kaminski, Tomasz; Kastner, Joel H.; Kerschbaum, Franz; Linsky,
   Jeffrey; Lopez, Bruno; Monnier, John; Montargès, Miguel; Nielsen,
   Krister; Ohnaka, Keiichi; Ramstedt, Sofia; Roettenbacher, Rachael;
   ten Brummelaar, Theo; Paladini, Claudia; Sarangi, Arkaprabha; van
   Belle, Gerard; Ventura, Paolo
Bibcode: 2019BAAS...51c.241R
Altcode: 2019arXiv190304585R; 2019astro2020T.241R
  This White Paper identifies compelling scientific opportunities in
  the field of Cool, Evolved Stars, describing the observational and
  theoretical challenges to our understanding, and the key advancements
  made. We portray the pathway towards understanding, and identify,
  through recommendations, which advancements are necessary in 2020-2030
  &amp; beyond.

Title: Stars at High Spatial Resolution
Authors: Carpenter, Kenneth; van Belle, Gerard; Brown, Alexander;
   Cranmer, Steven R.; Drake, Jeremy; Dupree, Andrea K.; Creech-Eakman,
   Michelle; Evans, Nancy R.; Grady, Carol A.; Guinan, Edward F.; Harper,
   Graham; Karovska, Margarita; Kolenberg, Katrien; Labeyrie, Antoine;
   Linsky, Jeffrey; Peters, Geraldine J.; Rau, Gioia; Ridgway, Stephen;
   Roettenbacher, Rachael M.; Saar, Steven H.; Walter, Frederick M.;
   Wood, Brian
Bibcode: 2019BAAS...51c..56C
Altcode: 2019astro2020T..56C
  We summarize compelling new scientific opportunities for understanding
  stars and stellar systems that can be enabled by sub-milliarcsec angular
  resolution, UV/Optical spectral imaging observations. These can reveal
  details of many dynamic processes that affect stellar formation,
  structure, and evolution.

Title: High Angular Resolution Astrophysics: Resolving Stellar
    Surface Features
Authors: Roettenbacher, Rachael; Norris, Ryan; Baron, Fabien;
   Carpenter, Kenneth; Creech-Eakman, Michelle; Gies, Douglas; Maccarone,
   Thomas; Monnier, John; Rau, Gioia; Ridgway, Stephen; Schaefer, Gail;
   ten Brummelaar, Theo
Bibcode: 2019BAAS...51c.181R
Altcode: 2019arXiv190304660R; 2019astro2020T.181R
  We discuss the main types of stars for which imaging surface features
  is currently possible using long-baseline optical interferometry and
  what improved observing techniques would provide for imaging stellar
  surface features.

Title: Characterizing Component Performance in the Lunar Environment
Authors: Patterson, M. C. L.; Tucker, J.; Carpenter, K.; Parness, A.
Bibcode: 2019LPI....50.2756P
Altcode:
  Understanding how systems perform on planetary surfaces is critical to
  mission success. Simulated lunar environments allow accurate component
  life predictions.

Title: The Wide Field Infrared Survey Telescope: 100 Hubbles for
    the 2020s
Authors: Akeson, Rachel; Armus, Lee; Bachelet, Etienne; Bailey,
   Vanessa; Bartusek, Lisa; Bellini, Andrea; Benford, Dominic; Bennett,
   David; Bhattacharya, Aparna; Bohlin, Ralph; Boyer, Martha; Bozza,
   Valerio; Bryden, Geoffrey; Calchi Novati, Sebastiano; Carpenter,
   Kenneth; Casertano, Stefano; Choi, Ami; Content, David; Dayal,
   Pratika; Dressler, Alan; Doré, Olivier; Fall, S. Michael; Fan,
   Xiaohui; Fang, Xiao; Filippenko, Alexei; Finkelstein, Steven; Foley,
   Ryan; Furlanetto, Steven; Kalirai, Jason; Gaudi, B. Scott; Gilbert,
   Karoline; Girard, Julien; Grady, Kevin; Greene, Jenny; Guhathakurta,
   Puragra; Heinrich, Chen; Hemmati, Shoubaneh; Hendel, David; Henderson,
   Calen; Henning, Thomas; Hirata, Christopher; Ho, Shirley; Huff,
   Eric; Hutter, Anne; Jansen, Rolf; Jha, Saurabh; Johnson, Samson;
   Jones, David; Kasdin, Jeremy; Kelly, Patrick; Kirshner, Robert;
   Koekemoer, Anton; Kruk, Jeffrey; Lewis, Nikole; Macintosh, Bruce;
   Madau, Piero; Malhotra, Sangeeta; Mandel, Kaisey; Massara, Elena;
   Masters, Daniel; McEnery, Julie; McQuinn, Kristen; Melchior, Peter;
   Melton, Mark; Mennesson, Bertrand; Peeples, Molly; Penny, Matthew;
   Perlmutter, Saul; Pisani, Alice; Plazas, Andrés; Poleski, Radek;
   Postman, Marc; Ranc, Clément; Rauscher, Bernard; Rest, Armin; Roberge,
   Aki; Robertson, Brant; Rodney, Steven; Rhoads, James; Rhodes, Jason;
   Ryan, Russell, Jr.; Sahu, Kailash; Sand, David; Scolnic, Dan; Seth,
   Anil; Shvartzvald, Yossi; Siellez, Karelle; Smith, Arfon; Spergel,
   David; Stassun, Keivan; Street, Rachel; Strolger, Louis-Gregory;
   Szalay, Alexander; Trauger, John; Troxel, M. A.; Turnbull, Margaret;
   van der Marel, Roeland; von der Linden, Anja; Wang, Yun; Weinberg,
   David; Williams, Benjamin; Windhorst, Rogier; Wollack, Edward; Wu,
   Hao-Yi; Yee, Jennifer; Zimmerman, Neil
Bibcode: 2019arXiv190205569A
Altcode:
  The Wide Field Infrared Survey Telescope (WFIRST) is a 2.4m space
  telescope with a 0.281 deg^2 field of view for near-IR imaging and
  slitless spectroscopy and a coronagraph designed for &gt; 10^8 starlight
  suppresion. As background information for Astro2020 white papers,
  this article summarizes the current design and anticipated performance
  of WFIRST. While WFIRST does not have the UV imaging/spectroscopic
  capabilities of the Hubble Space Telescope, for wide field near-IR
  surveys WFIRST is hundreds of times more efficient. Some of the most
  ambitious multi-cycle HST Treasury programs could be executed as
  routine General Observer (GO) programs on WFIRST. The large area and
  time-domain surveys planned for the cosmology and exoplanet microlensing
  programs will produce extraordinarily rich data sets that enable an
  enormous range of Archival Research (AR) investigations. Requirements
  for the coronagraph are defined based on its status as a technology
  demonstration, but its expected performance will enable unprecedented
  observations of nearby giant exoplanets and circumstellar disks. WFIRST
  is currently in the Preliminary Design and Technology Completion phase
  (Phase B), on schedule for launch in 2025, with several of its critical
  components already in production.

Title: M-Giant Mass-Loss Rates and Wind Parameters from UV Emission
    Line Profiles
Authors: Carpenter, Kenneth G.; Rau, Gioia; Nielsen, Krister E.
Bibcode: 2019AAS...23336506C
Altcode:
  Strong chromospheric emission lines in the UV spectra of M giants show
  superposed absorption features created by their photon-scattering
  winds. These self-reversed emission profiles provide us with an
  opportunity to assess important parameters of the wind, including
  flow and turbulent velocities, the optical depth of the wind above
  the region of photon creation, and the star's mass-loss rate. We use
  the Sobolev with Exact Integration (SEI) radiative transfer code,
  along with simple models of the outer atmospheric structure and
  wind, to determine the wind characteristics of the two M-giant stars
  Gamma Cru (M3.4) and Mu Gem (M3IIIab). We use this code because it
  is computationally fast and allows a great number of possible wind
  models to be examined. The program calculates line profiles for the
  Mg II (UV1) lines and a range of unblended Fe II lines. These lines
  represent a wide range of wind opacities, and thus different heights
  in the atmosphere. The assumed wind properties are iterated, until
  the predicted profiles match the observations (in this case HST/GHRS
  UV spectra), over as many lines as possible. We present estimates of
  the wind parameters for these two M-giant stars, and offer a comparison
  to wind properties previously-determined for low-gravity K stars using
  the same technique and similar data.

Title: Key Technologies for the Wide Field Infrared Survey Telescope
    Coronagraph Instrument
Authors: Bailey, Vanessa P.; Armus, Lee; Balasubramanian, Bala;
   Baudoz, Pierre; Bellini, Andrea; Benford, Dominic; Berriman, Bruce;
   Bhattacharya, Aparna; Boccaletti, Anthony; Cady, Eric; Calchi Novati,
   Sebastiano; Carpenter, Kenneth; Ciardi, David; Crill, Brendan; Danchi,
   William; Debes, John; Demers, Richard; Dohlen, Kjetil; Effinger,
   Robert; Ferrari, Marc; Frerking, Margaret; Gelino, Dawn; Girard,
   Julien; Grady, Kevin; Groff, Tyler; Harding, Leon; Helou, George;
   Henning, Avenhaus; Janson, Markus; Kalirai, Jason; Kane, Stephen;
   Kasdin, N. Jeremy; Kenworthy, Matthew; Kern, Brian; Krist, John;
   Kruk, Jeffrey; Lagrange, Anne Marie; Laine, Seppo; Langlois, Maud;
   Le Coroller, Herve; Lindensmith, Chris; Lowrance, Patrick; Maire,
   Anne-Lise; Malhotra, Sangeeta; Mandell, Avi; McElwain, Michael;
   Mejia Prada, Camilo; Mennesson, Bertrand; Meshkat, Tiffany; Moody,
   Dwight; Morrissey, Patrick; Moustakas, Leonidas; N'Diaye, Mamadou;
   Nemati, Bijan; Noecker, Charley; Paladini, Roberta; Perrin, Marshall;
   Poberezhskiy, Ilya; Postman, Marc; Pueyo, Laurent; Ramirez, Solange;
   Ranc, Clement; Rhodes, Jason; Riggs, A. J. E.; Rizzo, Maxime; Roberge,
   Aki; Rouan, Daniel; Schlieder, Joshua; Seo, Byoung-Joon; Shaklan,
   Stuart; Shi, Fang; Soummer, Remi; Spergel, David; Stapelfeldt, Karl;
   Stark, Christopher; Tamura, Motohide; Tang, Hong; Trauger, John;
   Turnbull, Margaret; van der Marel, Roeland; Vigan, Arthur; Williams,
   Benjamin; Wollack, Edward J.; Ygouf, Marie; Zhao, Feng; Zhoud, Hanying;
   Zimmerman, Neil
Bibcode: 2019arXiv190104050B
Altcode:
  The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument
  (CGI) is a high-contrast imager and integral field spectrograph
  that will enable the study of exoplanets and circumstellar disks at
  visible wavelengths. Ground-based high-contrast instrumentation has
  fundamentally limited performance at small working angles, even under
  optimistic assumptions for 30m-class telescopes. There is a strong
  scientific driver for better performance, particularly at visible
  wavelengths. Future flagship mission concepts aim to image Earth
  analogues with visible light flux ratios of more than 10^10. CGI
  is a critical intermediate step toward that goal, with a predicted
  10^8-9 flux ratio capability in the visible. CGI achieves this through
  improvements over current ground and space systems in several areas:
  (i) Hardware: space-qualified (TRL9) deformable mirrors, detectors,
  and coronagraphs, (ii) Algorithms: wavefront sensing and control;
  post-processing of integral field spectrograph, polarimetric, and
  extended object data, and (iii) Validation of telescope and instrument
  models at high accuracy and precision. This white paper, submitted to
  the 2018 NAS Exoplanet Science Strategy call, describes the status of
  key CGI technologies and presents ways in which performance is likely
  to evolve as the CGI design matures.

Title: HST/GHRS Observations of Cool, Low-gravity Stars. VI. Mass-loss
    Rates and Wind Parameters for M Giants
Authors: Rau, Gioia; Nielsen, Krister E.; Carpenter, Kenneth G.;
   Airapetian, Vladimir
Bibcode: 2018ApJ...869....1R
Altcode: 2018arXiv181110679R
  The photon-scattering winds of M giants absorb parts of the
  chromospheric emission lines and produce self-reversed spectral features
  in high-resolution Hubble Space Telescope (HST)/GHRS spectra. These
  spectra provide an opportunity to assess fundamental parameters of the
  wind, including flow and turbulent velocities, the optical depth of the
  wind above the region of photon creation, and the star’s mass-loss
  rate. This paper is the last paper in the series “GHRS Observations
  of Cool, Low-Gravity Stars” the last several have compared empirical
  measurements of spectral emission lines with models of the winds and
  mass loss of K giants and supergiants. We have used the Sobolev with
  Exact Integration radiative transfer code, along with simple models
  of the outer atmosphere and wind, to determine and compare the wind
  characteristics of the two M-giant stars, γ Cru (M3.5III) and μ Gem
  (M3IIIab), with previously derived values for low-gravity K-stars. The
  analysis specifies the wind parameters and calculates line profiles
  for the Mg II resonance lines, in addition to a range of unblended
  Fe II lines. Our line sample covers a large range of wind opacities
  and, therefore, probes a range of heights in the atmosphere. Our
  results show that μ Gem has a slower and more turbulent wind than γ
  Cru. Also, μ Gem has a weaker chromosphere, in terms of surface flux,
  with respect to γ Cru. This suggests that μ Gem is more evolved
  than γ Cru. Comparing the two M giants in this work with previously
  studied K-giant and supergiant stars (α Tau, γ Dra, and λ Vel)
  reveals that the M giants have slower winds than the earlier giants,
  but exhibit higher mass-loss rates. Our results are interpreted in
  the context of the winds being driven by Alfvén waves.

Title: The Advanced Spectral Library (ASTRAL): Reference Spectra
    for Evolved M Stars
Authors: Carpenter, Kenneth G.; Nielsen, Krister E.; Kober, Gladys V.;
   Ayres, Thomas R.; Wahlgren, Glenn M.; Rau, Gioia
Bibcode: 2018ApJ...869..157C
Altcode: 2018arXiv181111865C
  The HST Treasury Program Advanced Spectral Library Project: Cool Stars
  was designed to collect representative, high-quality UV spectra of eight
  evolved F-M type cool stars. The Space Telescope Imaging Spectrograph
  (STIS) echelle spectra of these objects enable investigations of a broad
  range of topics, including stellar and interstellar astrophysics. This
  paper provides a guide to the spectra of the two evolved M stars, the
  M2 Iab supergiant α Ori and the M3.4 giant γ Cru, with comparisons to
  the prototypical K1.5 giant α Boo. It includes identifications of the
  significant atomic and molecular emission and absorption features and
  discusses the character of the photospheric and chromospheric continua
  and line spectra. The fluorescent processes responsible for a large
  portion of the emission-line spectrum, the characteristics of the
  stellar winds, and the available diagnostics for hot and cool plasmas
  are also summarized. This analysis will facilitate the future study of
  the spectra, outer atmospheres, and winds, not only of these objects
  but of numerous other cool, low-gravity stars, for years to come. <P
  />Based on observations with the NASA/ESA Hubble Space Telescope
  obtained at the Space Telescope Science Institute, which is operated
  by the Association of Universities for Research in Astronomy, Inc.,
  under NASA contract NAS5-26555.

Title: Shifting the Paradigm of Coping with Nyx on the Moon — a
    Ground-Penetrating Radar Case
Authors: Nunes, D. C.; Carpenter, K.; Haynes, M.; de la Croix, J. P.
Bibcode: 2018LPICo2106.7012N
Altcode:
  A multi-static, autonomous ground-penetrating radar instrument, MARGE,
  will incorporate strategies to be more tolerant of the lunar diurnal
  thermal cycle.

Title: The Mass of the Cepheid V350 Sgr
Authors: Evans, Nancy Remage; Proffitt, Charles; Carpenter, Kenneth G.;
   Winston, Elaine M.; Kober, Gladys V.; Günther, H. Moritz; Gorynya,
   Natalia; Rastorguev, Alexey; Inno, L.
Bibcode: 2018ApJ...866...30E
Altcode: 2018arXiv180810472E
  V350 Sgr is a classical Cepheid suitable for mass determination. It has
  a hot companion which is prominent in the ultraviolet (UV) and which
  is not itself a binary. We have obtained two high-resolution echelle
  spectra of the companion at orbital velocity maximum and minimum with
  the Space Telescope Imaging Spectrograph on the Hubble Space Telescope
  in the 1320 to 1510 Å region. By cross-correlating these spectra
  we obtained the orbital velocity amplitude of the companion with an
  uncertainty in the companion amplitude of 1.9 km s<SUP>-1</SUP>. This
  provides a mass ratio of the Cepheid to the companion of 2.1. The UV
  energy distribution of the companion provides the mass of the companion,
  yielding a Cepheid mass of 5.2 ± 0.3 M <SUB>⊙</SUB>. This mass
  requires some combination of moderate main sequence core convective
  overshoot and rotation to match evolutionary tracks. <P />Based on
  observations with the NASA/ESA Hubble Space Telescope obtained at the
  Space Telescope Science Institute, which is operated by the Association
  of Universities for Research in Astronomy, Inc., under NASA contract
  NAS5-26555.

Title: Imaging the Surfaces of Stars from Space
Authors: Carpenter, Kenneth; Rau, Gioia
Bibcode: 2018iss..confE...4C
Altcode:
  Imaging of Stellar Surfacess has been dominated to-date by ground-based
  observations, but space-based facilities offer tremendous potential for
  extending the wavelength coverage and ultimately the resolution of such
  efforts. We review the imaging accomplished so far from space and then
  talk about exciting future prospects. The earliest attempts from space
  indirectly produced surface maps via the Doppler Imaging Technique,
  using UV spectra obtained with the International Ultraviolet Explorer
  (IUE). Later, the first direct UV images were obtained with the Hubble
  Space Telescope (HST), of Mira and Betelgeuse, using the Faint Object
  Camera (FOC). We will show this work and then investigate prospects
  for IR imaging with the James Webb Space Telescope (JWST). The real
  potential of space-based Imaging of Stellar Surfacess, however, lies
  in the future, when large-baseline Fizeau interferometers, such as the
  UV-optical Stellar Imager (SI) Vision Mission, with a 30-element array
  and 500m max baseline, are flown. We describe SI and its science goals,
  which include 0.1 milli-arcsec spectral Imaging of Stellar Surfacess
  and the probing of internal structure and flows via asteroseismology.

Title: The WFIRST Exoplanet Microlensing Survey
Authors: Bennett, David P.; Akeson, Rachel; Anderson, Jay; Armus,
   Lee; Bachelet, Etienne; Bailey, Vanessa; Barclay, Thomas; Barry,
   Richard; Beaulieu, Jean-Phillipe; Belini, Andrea; Benford, Dominic
   J.; Bhattacharya, Aparna; Boyd, Padi; Bozza, Valerio; Calchi Novati,
   Sebastiano; Carpenter, Kenneth; Cassan, Arnaud; Ciardi, David; Cole,
   Andrew; Colon, Knicole; Coutures, Christian; Dominik, Martin; Fouque,
   Pascal; Grady, Kevin; Groff, Tyler; Henderson, Calen B.; Horne,
   Keith; Gelino, Christopher; Gelino, Dawn; Kalirai, Jason; Kane,
   Stephen; Kasdin, N. Jeremy; Kruk, Jeffrey; Laine, Seppo; Lambrechts,
   Michiel; Mancini, Luigi; Mandell, Avi; Malhotra, Sangeeta; Mao, Shude;
   McElwain, Michael; Mennesson, Bertrand; Meshkat, Tiffany; Moustakas,
   Leonidas; Munoz, Jose A.; Nataf, David; Paladini, Roberta; Pascucci,
   Ilaria; Penny, Matthew; Poleski, Radek; Quintana, Elisa; Ranc, Clement;
   Rattenbury, Nicholas; Rhodes, James; Rhodes, Jason D.; Rizzo, Maxime;
   Roberge, Aki; Rogers, Leslie; Sahu, Kailash C.; Schlieder, Joshua;
   Seager, Sara; Shvartzvald, Yossi; Soummer, Remi; Spergel, David;
   Stassun, Keivan G.; Street, Rachel; Sumi, Takahiro; Suzuki, Daisuke;
   Trauger, John; van der Marel, Roeland; Williams, Benjamin F.; Wollack,
   Edward J.; Yee, Jennifer; Yonehara, Atsunori; Zimmerman, Neil
Bibcode: 2018arXiv180308564B
Altcode:
  The Wide Field Infrared Survey Telescope (WFIRST) was the top ranked
  large space mission in the 2010 New Worlds, New Horizons decadal survey,
  and it was formed by merging the science programs of 3 different
  mission concepts, including the Microlensing Planet Finder (MPF)
  concept (Bennett \etal\ 2010). The WFIRST science program (Spergel
  \etal\ 2015) consists of a general observer program, a wavefront
  controlled technology program, and two targeted science programs: a
  program to study dark energy, and a statistical census of exoplanets
  with a microlensing survey, which uses nearly one quarter of WFIRST's
  observing time in the current design reference mission. The New Worlds,
  New Horizons (decadal survey) midterm assessment summarizes the science
  case for the WFIRST exoplanet microlensing survey with this statement:
  "WFIRST's microlensing census of planets beyond 1 AU will perfectly
  complement Kepler's census of compact systems, and WFIRST will also
  be able to detect free-floating planets unbound from their parent
  stars\rlap."

Title: Weighing supermassive black holes with the UV photon sieve
    space telescope
Authors: Airapetian, Vladimir; Upton, Robert S.; Davila, Joseph;
   Marzouk, Marzouk; Carpenter, Kenneth G.; Weaver, Kimberly
Bibcode: 2017SPIE10564E..3RA
Altcode:
  The Photon Sieve Space Telescope (PSST) is a space-based ultra
  high-resolution (5 mas) narrow band (λ/Δλ ≃ 1000) spectral UV
  imager providing spectral imaging of astronomical objects in Ly - ,
  CIV and NV emission lines. Science obtained with this telescope will
  revolutionize our understanding of a whole range of astrophysical
  processes in the local and distant universe. There will be a dramatic
  increase in the number of observed moderate and large SMBH masses as
  well as extra-solar protoplanetary disks. The observations will also
  enable tracing the star formation rates in active galaxies. We present
  the optical design, the properties and the future implementation of
  the proposed UV photon sieve space telescope.

Title: Detecting the Beacons of Life with Exo-Life Beacon Space
    Telescope (ELBST)
Authors: Airapetian, V. S.; Danchi, W. C.; Chen, P. C.; Rabin, D. M.;
   Carpenter, K. G.; Mlynczak, M. G.
Bibcode: 2017LPICo1989.8214A
Altcode:
  We propose a new observational strategy, the “Exo-Life Beacon Space
  Telescope,” for detecting the signatures of “beacons” of life
  defined as high signal and low spectral resolution thermal emission
  from molecules associated with life signatures.

Title: Bridging the Gap between Coronal and Non-Coronal Evolved Stars
Authors: Carpenter, Kenneth G.; Nielsen, Krister E.; Kober, Gladys V.
Bibcode: 2017AAS...22915102C
Altcode:
  The Hubble Space Telescope (HST) Treasury Program "Advanced Spectral
  Library (ASTRAL)" enables investigations of a broad range of problems
  including the character and dynamics of the wind and chromosphere
  of cool stars. This paper presents an investigation of the change in
  spectral characteristics when transitioning from the cool non-coronal
  objects with fluorescent emission spectra from the iron group elements,
  molecular hydrogen, and carbon monoxide to the warmer stars on the
  blue side of the Linsky-Haish dividing line in the HR diagram. These
  warmer objects exhibit chromospheric emission from significantly
  hotter environments in addition to coronal signatures, while the hybrid
  stars overlap in the HR-diagram with some of the non-coronal objects
  and share many spectral characteristics but show differences in the
  wind properties. We show how the wind, fluorescent features, and hot
  stellar signatures dramatically change with spectral class by comparing
  the already analyzed non-coronal objects (Alpha Ori, Gamma Cru) with
  the hybrid stars (Gamma Dra, Beta Gem and Alpha Aqr) and the coronal
  object Beta Dra. We aim to gain understanding of the physical processes
  in these objects' outer atmospheres and their evolutionary tracks.

Title: A Precision Measurement of the Mass of the Cepheid V350 Sgr
Authors: Evans, Nancy Remage; Bono, Giuseppe; Carpenter, Kenneth G.;
   Gorynya, Natashya; Inno, Laura; Proffitt, Charles R.; Rastorgouev,
   Alexey
Bibcode: 2016hst..prop14332E
Altcode:
  An important HST UV legacy is the measurement of the masses of
  Cepheids. HST has provided double-lined spectroscopic binaries since the
  orbital velocity amplitude of hot companions can be measured on high
  resolution ultraviolet spectra. STIS UV E140H echelle observations of
  the Cepheid V350 Sgr will yield a dramatic improvement in the precision
  of its mass (5% or 0.25 solar masses vs the current 17%). This will
  allow a unique and critical test of the role of convective overshoot
  in the evolution of intermediate mass stars, by coupling the measured
  mass with a luminosity. Furthermore, the very accurate masses (1-2%)
  recently determined for two Cepheids in eclipsing binaries in the LMC
  mean the mass--luminosity relation for Cepheids can be compared for
  two metallicities. This will improve both confidence in the use of
  Cepheids as primary extragalactic distance indicators and also our
  understanding of the evolution of intermediate mass stars.

Title: PUFFER (Pop-Up Flat Folding Explorer Robots)
Authors: Karras, J.; Carpenter, K.; Fuller, C.; Parcheta, C.
Bibcode: 2016LPICo1980.4125K
Altcode:
  PUFFER (Pop-Up Flat Folding Explorer Robots) are origami-inspired
  folding robots with extreme terrain mobility. PUFFERs are low-volume,
  low-mass, and low-cost robots for high-reward extreme terrain science.

Title: Highlights of IAU Commission 29: Recent Advances and
    Perspectives on Stellar Spectroscopy
Authors: Cunha, Katia; Soderblom, David R.; Piskunov, Nikolai; Aoki,
   Wako; Asplund, Martin; Carpenter, Kenneth G.; Crowther, Paul; Melendez,
   Jorge; Venn, Kimberly; Hill, Vanessa; Yong, David
Bibcode: 2016IAUTA..29..428C
Altcode:
  IAU Commission 29 - Stellar Spectra has been one of the IAU commissions
  from the onset, until its dissolution at the most recent IAU General
  Assembly in Honolulu in 2015. This commission belonged to IAU Division
  G (``Stars and Stellar Physics''), the latter committed with fostering
  research in stellar astrophysics. Within the general field of stellar
  astrophysics, stellar spectroscopy plays a key role, as stellar
  spectra are a powerful tool providing a view into the detailed physical
  properties of stars and the physical processes occuring within them.

Title: Lithium in Open Cluster Red Giants Hosting Substellar
    Companions
Authors: Carlberg, Joleen K.; Smith, Verne V.; Cunha, Katia; Carpenter,
   Kenneth G.
Bibcode: 2016ApJ...818...25C
Altcode: 2015arXiv151208558C
  We have measured stellar parameters, [Fe/H], lithium abundances,
  rotation, and <SUP>12</SUP>C/<SUP>13</SUP>C in a small sample of
  red giants (RGs) in three open clusters that are each home to
  a RG star that hosts a substellar companion (SSC) (NGC 2423 3,
  NGC 4349 127, and BD+12 1917 in M67). Our goal is to explore
  whether the presence of SSCs influences the Li content. Both
  <SUP>12</SUP>C/<SUP>13</SUP>C and stellar rotation are measured as
  additional tracers of stellar mixing. One of the companion hosts,
  NGC 2423 3, is found to be Li-rich with A(Li){}<SUB>{{NLTE</SUB>}} =
  1.56 dex, and this abundance is significantly higher than the A(Li)
  of the two comparison stars in NGC 2423. All three SSC hosts have the
  highest A(Li) and <SUP>12</SUP>C/<SUP>13</SUP>C when compared to the
  control RGs in their respective clusters; however, except for NGC 2423
  3, at least one control star has similarly high abundances within the
  uncertainties. Higher A(Li) could suggest that the formation or presence
  of planets plays a role in the degree of internal mixing on or before
  the RG branch. However, a multitude of factors affect A(Li) during the
  RG phase, and when the abundances of our sample are compared with the
  abundances of RGs in other open clusters available in the literature,
  we find that they all fall well within a much larger distribution of
  A(Li) and <SUP>12</SUP>C/<SUP>13</SUP>C. Thus, even the high Li in
  NGC 2423 3 cannot be concretely tied to the presence of the SSC.

Title: The Advanced Spectral Library (ASTRAL): Abundance Analysis
    of the CP Star HR 465
Authors: Carpenter, Kenneth G.; Nielsen, Krister E.; Kober, Gladys V.
Bibcode: 2016AAS...22743401C
Altcode:
  We present the results of a spectrum analysis of the prototypical
  A-type magnetic CP star HR465. Synthetic spectra, using an non-LTE
  atmosphere model, were generated to fit high-resolution ultraviolet
  spectra (1200-3100 A) obtained as a part of the "Advanced Spectral
  Library (ASTRAL) Project: Hot Stars" program (GO-13346: Ayres
  PI). The ultraviolet data were supplemented by high resolution
  optical data recorded at the Nordic Optical Telescope with the SOFIN
  spectrograph. The optical data was used as a complement to the high
  line density ultraviolet spectrum and primarily used to derive accurate
  iron-group element abundances.HR 465 has previously been analyzed
  using IUE spectra. We revisit the object with this high quality
  data. Large parts of the spectrum have been synthesized with an ATLAS
  model (Teff=10750K, logg=4.0) and we present abundance results for more
  than 50 elements. We can confirm some of the abundance characteristics
  previously derived from IUE data, where elements heavier than Z=30
  show significant abundance enhancements compared to solar values,
  while some of the lighter elements show abundance deficiencies. We
  will place these results in context of other AP stars, and the large
  number of element abundances will also help us to put some constraint
  on stellar abundance and evolution theories.

Title: The Magnetic Coupling of Chromospheres and Winds From Late
Type Evolved Stars: Role of MHD Waves
Authors: Airapetian, Vladimir; Leake, James; Carpenter, Kenneth
Bibcode: 2015IAUGA..2190977A
Altcode:
  Stellar chromospheres and winds represent universal attributes
  of stars on the cool portion of H-R diagram. In this paper we
  derive observational constrains for the chromospheric heating and
  wind acceleration from cool evolved stars and examine the role of
  Alfven waves as a viable source of energy dissipation and momentum
  deposition. We use a 1.5D magnetohydrodynamic code with a generalized
  Ohm's law to study propagation of Alfven waves generated along
  a diverging magnetic field in a stellar photosphere at a single
  frequency. We demonstrate that due to inclusion of the effects of
  ion-neutral collisions in magnetized weakly ionized chromospheric
  plasma on resistivity and the appropriate grid resolution, the numerical
  resistivity becomes 1-2 orders of magnitude smaller than the physical
  resistivity. The motions introduced by non-linear transverse Alfven
  waves can explain non-thermally broadened and non-Gaussian profiles
  of optically thin UV lines forming in the stellar chromosphere of
  α Tau and other late-type giant and supergiant stars. The calculated
  heating rates in the stellar chromosphere model due to resistive (Joule)
  dissipation of electric currents on Pedersen resistivity are consistent
  with observational constraints on the net radiative losses in UV lines
  and the continuum from α Tau. At the top of the chromosphere, Alfven
  waves experience significant reflection, producing downward propagating
  transverse waves that interact with upward propagating waves and produce
  velocity shear in the chromosphere. Our simulations also suggest that
  momentum deposition by non-linear Alfven waves becomes significant in
  the outer chromosphere within 1 stellar radius from the photosphere
  that initiates a slow and massive winds from red giants and supergiants.

Title: The abundance pattern of heavy elements in Sirius: Impact of
    modern observations (STIS) and improved Atomic data
Authors: Ramsay Cowley, Charles; Ayres, Thomas; Wahlgren, Glenn;
   Carpenter, Kenneth
Bibcode: 2015IAUGA..2236931R
Altcode:
  The abundance pattern of heavy elements in Sirius: Impact of modern
  observations (STIS) and improved atomic data. We determine abundances
  or upper limits for the 55 stable elements from copper to uranium for
  the A1 Vm star Sirius. The primary observational material consists of
  Hubble Space Telescope (HST) spectra taken with the Space Telescope
  Imaging Spectrograph (STIS) from the ASTRAL project (Ayres 2010,
  ApJS, 187, 149). We have also used archival material from COPERNICUS
  (retrieved from the MAST) and from HST/GHRS, as well as the ground-based
  Furenlid, Westin, and Kurucz Sirius Atlas (FWK). The GHRS observations
  were described by Wahlgren, et al. (1993, Bull. AAS, 25, 1321). We
  also used the monumental study of Sirius by Klaus Kohl (1964,
  Zs. f. Ap. 60, 115, 1964, see also 1964, Das Spektrum des Sirius,
  3100 - 8863A, Kiel thesis). Abundance determinations are based on
  the photospheric model of Landstreet (2011, A&amp;A, 528, 132). The
  atomic data base is significantly improved since the pioneering work
  by Sadakane (1988, PASP, 100, 811; 1991, 103, 355). The basic source
  was VALD3 (http://vald.inasan.ru/~vald3/php/vald.php), supplemented
  for all species by the essential NIST bibliographic data base
  (http://physics.nist.gov/cgi-bin/ASBib1/TransProbBib.cgi). We determine
  abundances and upper limits by synthesizing short wavelength regions
  around strong lines. Virtually all of the abundance/upper limit results
  show excesses over the solar composition of between 1 and 2 dex. This
  result is in general agreement with overall results for metallic line
  stars, though we have no information on possible severe depletions
  for most elements. We conclude that the mechanisms causing abundance
  anomalies in Sirius have not acted to produce the extreme excesses of 4
  or more dex (Pt, Hg), or deficiencies (Zn) seen in many HgMn stars.CRC
  thanks Stefano Bagnulo for the UVESPOP Sirius spectrum. Robert Kurucz
  was most helpful with older Sirius UV and visual spectra.

Title: Fluorescence Processes in the Outer Atmospheres of the Evolved
    M-Stars Alpha Ori (M2 Iab) and Gamma Cru (M3.4 III)
Authors: Carpenter, Kenneth; Kober, Gladys; Nielsen, Krister; Ayres,
   Thomas; Wahlgren, Glenn
Bibcode: 2015IAUGA..2242446C
Altcode:
  The prototypical M-giant and M-supergiant stars, Gamma Cru (M3.4
  III)) and Alpha Ori (M2Iab), have been observed as part of the
  "Advanced Spectral Library (ASTRAL) Project: Cool Stars" (PI =
  T. Ayres). "ASTRAL-Cool Stars" is an HST Cycle 18 Treasury Program
  designed to collect, using the Space Telescope Imaging Spectrograph
  (STIS), a definitive set of representative, high-resolution (R~46,000
  in the FUV up to ~1700 Å, R~30,000 for 1700-2150 Å, and R~114,000
  &gt;2150 Å) and high signal/noise (S/N&gt;100) UV spectra of eight F-M
  evolved cool stars. These extremely high-quality UV echelle spectra
  are available from the HST archive and through the University of
  Colorado (http://casa.colorado.edu/~ayres/ASTRAL/). In this paper,
  we use the very rich emission-line spectra of the two evolved M stars
  in the sample, Gamma Cru (GaCrux) and Alpha Ori (Betelgeuse), to study
  the fluorescence processes operating in their outer atmospheres. We
  summarize the pumping transitions and fluorescent line products known
  on the basis of previous work and newly identified in our on-going
  analysis of these extraordinary new “Treasury” spectra. Detailed
  descriptions of selected processes are given to illustrate their
  operation. The wide variety of fluorescence processes in operation in
  these outer atmospheres, both molecular and atomic, suggest that there
  is a mixture of warm and cool plasmas present and that H I Ly-alpha in
  particular is locally very strong, even though, in the case of Alpha
  Ori, no flux is seen at earth due to strong circumstellar absorption
  at that wavelength. Many new fluorescence line products and several
  new processes have been identified in these spectra, which are more
  complete and of higher S/N than previously available for these stars.

Title: Wide-Field InfrarRed Survey Telescope-Astrophysics Focused
    Telescope Assets WFIRST-AFTA 2015 Report
Authors: Spergel, D.; Gehrels, N.; Baltay, C.; Bennett, D.;
   Breckinridge, J.; Donahue, M.; Dressler, A.; Gaudi, B. S.; Greene, T.;
   Guyon, O.; Hirata, C.; Kalirai, J.; Kasdin, N. J.; Macintosh, B.; Moos,
   W.; Perlmutter, S.; Postman, M.; Rauscher, B.; Rhodes, J.; Wang, Y.;
   Weinberg, D.; Benford, D.; Hudson, M.; Jeong, W. -S.; Mellier, Y.;
   Traub, W.; Yamada, T.; Capak, P.; Colbert, J.; Masters, D.; Penny,
   M.; Savransky, D.; Stern, D.; Zimmerman, N.; Barry, R.; Bartusek,
   L.; Carpenter, K.; Cheng, E.; Content, D.; Dekens, F.; Demers, R.;
   Grady, K.; Jackson, C.; Kuan, G.; Kruk, J.; Melton, M.; Nemati, B.;
   Parvin, B.; Poberezhskiy, I.; Peddie, C.; Ruffa, J.; Wallace, J. K.;
   Whipple, A.; Wollack, E.; Zhao, F.
Bibcode: 2015arXiv150303757S
Altcode:
  This report describes the 2014 study by the Science Definition Team
  (SDT) of the Wide-Field Infrared Survey Telescope (WFIRST) mission. It
  is a space observatory that will address the most compelling scientific
  problems in dark energy, exoplanets and general astrophysics using a
  2.4-m telescope with a wide-field infrared instrument and an optical
  coronagraph. The Astro2010 Decadal Survey recommended a Wide Field
  Infrared Survey Telescope as its top priority for a new large space
  mission. As conceived by the decadal survey, WFIRST would carry out
  a dark energy science program, a microlensing program to determine
  the demographics of exoplanets, and a general observing program
  utilizing its ultra wide field. In October 2012, NASA chartered
  a Science Definition Team (SDT) to produce, in collaboration with
  the WFIRST Study Office at GSFC and the Program Office at JPL, a
  Design Reference Mission (DRM) for an implementation of WFIRST using
  one of the 2.4-m, Hubble-quality telescope assemblies recently made
  available to NASA. This DRM builds on the work of the earlier WFIRST
  SDT, reported by Green et al. (2012) and the previous WFIRST-2.4 DRM,
  reported by Spergel et. (2013). The 2.4-m primary mirror enables a
  mission with greater sensitivity and higher angular resolution than
  the 1.3-m and 1.1-m designs considered previously, increasing both the
  science return of the primary surveys and the capabilities of WFIRST
  as a Guest Observer facility. The addition of an on-axis coronagraphic
  instrument to the baseline design enables imaging and spectroscopic
  studies of planets around nearby stars.

Title: Comparing Vent Surface Geometry with Its Subsurface Structure
Authors: Parcheta, C.; Parness, A.; Nash, J.; Wiltsie, N.; Carpenter,
   K.; Mitchell, K. L.
Bibcode: 2015LPI....46.1649P
Altcode: 2015LPICo1832.1649P
  Magma conduit./Shape is vital yet unknown./How does it erupt?

Title: The HST Treasury ``Advanced Spectral Library'' (ASTRAL)
    Programs
Authors: Carpenter, Kenneth G.; Ayres, Thomas R.
Bibcode: 2015csss...18.1041C
Altcode: 2014arXiv1411.1419C
  The ``Advanced Spectral Library (ASTRAL)'' Project (PI = T. Ayres)
  consists of two Treasury Programs: the Cycle 18 ``Cool Stars''
  (GO-12278) Program and the Cycle 21 ``Hot Stars'' (GO-13346)
  Program. The primary goal of these programs is to collect, for the use
  of the astronomical community over the coming decades, a definitive
  set of representative, high-resolution (R∼30,000-100,000), high
  signal/noise (S/N&gt;100) spectra, with full UV coverage (∼1150 -
  3100 Å) of prototypical stars across the HR diagram, utilizing the
  high-performance Space Telescope Imaging Spectrograph (STIS). The
  Cycle 18 program obtained spectra of 8 F-M evolved late-type
  stars, while the Cycle 21 program is in the process of observing
  21 early-type stars, which span a broad range of spectral types
  between early-O and early-A. All of these data will be available
  from the HST archive and, in post-processed and merged form, at
  http://casa.colorado.edu/ãyres/ASTRAL/. These data will enable
  investigations of a broad range of problems - stellar, interstellar,
  and beyond - for many years into the future. We describe here the
  details of the observing programs, including the program targets and the
  observing strategies utilized to optimize the quality of the spectra,
  and present some illustrative examples of the on-going scientific
  analyses, including a study of the outer atmospheres and winds of
  the two evolved M stars in the sample and a first look at a ``high
  definition'' UV spectrum of a magnetic chemically peculiar ``Ap'' star.

Title: Mining the HST "Advanced Spectral Library (ASTRAL)": Winds
    of the Evolved M Stars Alpha Ori (M2 Iab) and Gamma Cru (M3.4 III)
Authors: Carpenter, Kenneth G.; Nielsen, Krister E.; Kober, Gladys V.;
   Ayres, Thomas R.
Bibcode: 2015AAS...22534408C
Altcode:
  The "Advanced Spectral Library (ASTRAL) Project: Cool Stars" (PI
  = T. Ayres) is an HST Cycle 18 Treasury Program that collected a
  definitive set of representative, high-resolution (R=30,000-100,000)
  and high signal/noise (S/N&gt;100) UV spectra of eight F-M evolved
  cool stars. These extremely high-quality STIS UV echelle spectra are
  available from the HST archive and through the ASTRAL website at the
  University of Colorado at http://casa.colorado.edu/~ayres/ASTRAL/ and
  will enable investigations of a broad range of problems -- stellar,
  interstellar, and beyond -- for many years. In this paper, we examine
  the wealth of wind diagnostics contained in the very rich spectra
  of the two evolved M stars in the sample, the M3.4 III giant Gamma
  Crucis (GaCrux) and the M2 Iab supergiant Alpha Orionis (Betelgeuse)
  and characterize the winds at the time of these STIS observations in
  2011 and compare the results with those obtained from more limited data
  taken at earlier epochs with HST/GHRS and IUE. In particular we study
  the variation of the numerous Fe II profiles with intrinsic strength
  in the two stars. The shifting wavelengths of the wind absorptions
  relative to the emission peaks and the changes in relative strengths
  of the emission peaks reflect the acceleration of the wind from the
  base of the chromosphere. Although the characteristics of the Gamma
  Cru wind are relatively stable with time, the Alpha Ori wind outflow
  appears significantly smaller than seen by Carpenter et al. (1997,
  ApJ, 479, 970) in GHRS observations taken in 1992 (and in earlier IUE
  observations). There might in fact be evidence in these STIS spectra
  that the outflow has turned into an inflow, as reported at epochs
  prior to IUE by Boesgaard and Magnan (1975 ApJ 198, 369) and Boesgaard
  (1979 ApJ 232, 485) based on a limited number of lines in the extreme
  blue end of ground-based spectra.

Title: Toward A Self Consistent MHD Model of Chromospheres and Winds
    From Late Type Evolved Stars
Authors: Airapetian, V. S.; Leake, J. E.; Carpenter, Kenneth G.
Bibcode: 2015csss...18..269A
Altcode: 2014arXiv1409.3833A
  We present the first magnetohydrodynamic model of the stellar
  chromospheric heating and acceleration of the outer atmospheres
  of cool evolved stars, using α Tau as a case study. We used a
  1.5D MHD code with a generalized Ohm's law that accounts for the
  effects of partial ionization in the stellar atmosphere to study
  Alfvén wave dissipation and wave reflection. We have demonstrated
  that due to inclusion of the effects of ion-neutral collisions in
  magnetized weakly ionized chromospheric plasma on resistivity and
  the appropriate grid resolution, the numerical resistivity becomes
  1-2 orders of magnitude smaller than the physical resistivity. The
  motions introduced by non-linear transverse Alfvé waves can explain
  non-thermally broadened and non-Gaussian profiles of optically thin UV
  lines forming in the stellar chromosphere of α Tau and other late-type
  giant and supergiant stars. The calculated heating rates in the stellar
  chromosphere due to resistive (Joule) dissipation of electric currents,
  induced by upward propagating non-linear Alfvé waves, are consistent
  with observational constraints on the net radiative losses in UV lines
  and the continuum from α Tau. At the top of the chromosphere, Alfvé
  waves experience significant reflection, producing downward propagating
  transverse waves that interact with upward propagating waves and produce
  velocity shear in the chromosphere. Our simulations also suggest that
  momentum deposition by non-linear Alfvé waves becomes significant in
  the outer chromosphere at 1 stellar radius from the photosphere. The
  calculated terminal velocity and the mass loss rate are consistent
  with the observationally derived wind properties in α Tau.

Title: An HST COS "SNAPshot" Spectrum of the K Supergiant λ Vel
    (K4Ib-II)
Authors: Carpenter, Kenneth G.; Ayres, Thomas R.; Harper, Graham M.;
   Kober, Gladys; Nielsen, Krister E.; Wahlgren, Glenn M.
Bibcode: 2014ApJ...794...41C
Altcode:
  We present a far-ultraviolet spectrum of the K4 Ib-II supergiant λ Vel
  obtained with the Hubble Space Telescope's Cosmic Origins Spectrograph
  (COS) as a part of the SNAPshot program "SNAPing coronal iron" (GO
  11687). The observation covers a wavelength region (1326-1467 Å)
  not previously recorded for λ Vel at a spectral resolving power
  of R ~ 20,000 and displays strong emission and absorption features,
  superposed on a bright chromospheric continuum. Fluorescent excitation
  is responsible for much of the observed emission, mainly powered by
  strong H I Lyα and the O I (UV 2) triplet emission near λ1304. The
  molecular CO and H<SUB>2</SUB> fluorescences are weaker than in the
  early-K giant α Boo while the Fe II and Cr II lines, also pumped
  by H I Lyα, are stronger in λ Vel. This pattern of relative line
  strengths between the two stars is explained by the lower iron-group
  element abundance in α Boo, which weakens that star's Fe II and
  Cr II emission without reducing the molecular fluorescences. The
  λ Vel spectrum shows fluorescent Fe II, Cr II, and H<SUB>2</SUB>
  emission similar to that observed in the M supergiant α Ori, but
  more numerous well-defined narrow emissions from CO. The additional CO
  emissions are visible in the spectrum of λ Vel since that star does
  not have the cool, opaque circumstellar shells that surround α Ori
  and produce broad circumstellar CO (A-X) band absorptions that hide
  those emissions in the cooler star. The presence of Si IV emission in
  λ Vel indicates a ~8 × 10<SUP>4</SUP> K plasma that is mixed into
  the cooler chromosphere. Evidence of the stellar wind is seen in the
  C II λλ1334,1335 lines and in the blueshifted Fe II and Ni II wind
  absorption lines. Line modeling using Sobolev with Exact Integration for
  the C II lines indicates a larger terminal velocity (~45 versus ~30 km
  s<SUP>-1</SUP>) and turbulence (~27 versus &lt;21 km s<SUP>-1</SUP>)
  with a more quickly accelerating wind (β = 0.35 versus 0.7) at the
  time of this COS observation in 2010 than derived from Goddard High
  Resolution Spectrograph data obtained in 1994. The Fe II and Ni II
  absorptions are blueshifted by 7.6 km s<SUP>-1</SUP> relative to the
  chromospheric emission, suggesting formation in lower levels of the
  accelerating wind and their widths indicate a higher turbulence in
  the λ Vel wind compared to α Ori. <P />Based on observations with
  the NASA/ESA Hubble Space Telescope obtained at the Space Telescope
  Science Institute, which is operated by the Association of Universities
  for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.

Title: Interferometer evolution: imaging terras after building
    'little' experiments (INEVITABLE)
Authors: Rinehart, S.; Carpenter, K.; van Belle, G.; Unwin, S.
Bibcode: 2014SPIE.9146E..17R
Altcode:
  Perhaps one of the most ambitious long-term goals of the astronomical
  community is to map distant exoplanets. This will require instruments
  that provide sufficient angular resolution to place multiple pixels
  across an image of an exoplanet. Many other science programs also
  require orders of magnitude improvement in angular resolution, and for
  all of these, single aperture telescopes are impractical. In fact,
  the array of scientific goals that require high angular resolution
  makes interferometry inevitable. Here, we discuss some of the long-term
  science needs, and the implications for future interferometers, and
  then talk about some possible paths towards these future missions.

Title: Mining the HST "Advanced Spectral Library (ASTRAL) - Hot
Stars": The High Definition UV Spectrum of the Ap Star HR 465
Authors: Carpenter, Kenneth G.; Ayres, T. R.; Nielsen, K. E.; Kober,
   G. V.; Wahlgren, G. M.; Adelman, S. J.; Cowley, C. R.
Bibcode: 2014AAS...22315105C
Altcode:
  The "Advanced Spectral Library (ASTRAL) Project: Hot Stars" is a Hubble
  Space Telescope (HST) Cycle 21 Treasury Program (GO-13346: Ayres
  PI). It is designed to collect a definitive set of representative,
  high-resolution ( 30,000-100,000), high signal/noise (S/N&gt;100),
  and full UV coverage 1200 - 3000 A) spectra of 21 early-type stars,
  utilizing the high-performance Space Telescope Imaging Spectrograph
  (STIS). The targets span the range of spectral types between early-O
  and early-A, including both main sequence and evolved stars, fast
  and slow rotators, as well as chemically peculiar (CP) and magnetic
  objects. These extremely high-quality STIS UV echelle spectra will be
  available from the HST archive and, in post-processed and merged form,
  at http://casa.colorado.edu ayres/ASTRAL/. The UV "atlases" produced by
  this program will enable investigations of a broad range of problems --
  stellar, interstellar, and beyond -- for many years to come. We offer a
  first look at one of the earliest datasets to come out of this observing
  program, a "high definition" UV spectrum of the Ap star HR 465, which
  was chosen as a prototypical example of an A-type magnetic CP star. HR
  465 has a global magnetic field of ~2200 Gauss. Earlier analyses of IUE
  spectra show strong iron-peak element lines, along with heavy elements
  such as Ga and Pt, while being deficient in the abundance of some ions
  of low atomic number, such as carbon. We demonstrate the high quality
  of the ASTRAL data and present the identification of spectral lines
  for a number of elements. By comparison of the observed spectra with
  calculated spectra, we also provide estimates of element abundances,
  emphasizing heavy elements, and place these measurements in the context
  of earlier results for this and other Ap stars.

Title: Evolution of Stellar Coronae: From the Sun to a Red Giant
Authors: Airapetian, Vladimir; Leake, J. E.; Carpenter, K. G.
Bibcode: 2014AAS...22342401A
Altcode:
  All stars in the H-R diagram later than spectral class F5 possess a
  convective zone that provides a reservoir of mechanical energy to drive
  activity in layers above the photosphere and to shape its atmospheric
  structures. Cool stars on the main sequence are characterized by compact
  chromospheres/transition regions and extended coronae transitioning into
  stellar winds. As the star exhausts its hydrogen fuel and enters into a
  giant/supergiant phase of its life, its atmospheric structures change
  dramatically showing signatures of bloated chromospheres and compact
  coronae. What physical mechanisms are responsible for such a drastic
  transition from a "dwarf" chromosphere of a cool dwarf star into a
  "giant" chromosphere of an evolved giant? How does a "giant" corona of a
  dwarf star evolve into a "dwarf" corona" of a giant star? In this talk
  we present a unified picture of the evolution of stellar atmospheric
  structures as a cool stars moves from the main-sequence to a red giant
  phase. The results of our 2.5D magnetohydrodynamic (MHD) simulations
  suggest the dynamics of the emergence of magnetic flux into the
  atmospheres of cool stars is strongly dependent on surface gravity and
  the magnetic field. We simulate the dynamics of emergence of magnetic
  field in the Sun, a sug-giant and a giant star. Our simulations suggest
  that as the surface gravity becomes smaller and the magnetic field
  weaker as the star evolves, the magnetic flux cannot be transported
  high enough into the atmosphere to form an extended corona. Instead,
  it forms highly compact loops in the lower layers of bloated stellar
  chromospheres and heated by Alfven waves to coronal temperatures.

Title: Using ISS telescopes for electromagnetic follow-up of
    gravitational wave detections of NS-NS and NS-BH mergers
Authors: Camp, J.; Barthelmy, S.; Blackburn, L.; Carpenter, K. G.;
   Gehrels, N.; Kanner, J.; Marshall, F. E.; Racusin, J. L.; Sakamoto, T.
Bibcode: 2013ExA....36..505C
Altcode: 2013arXiv1304.3705C; 2013ExA...tmp...31C
  The International Space Station offers a unique platform for rapid and
  inexpensive deployment of space telescopes. A scientific opportunity
  of great potential later this decade is the use of telescopes for the
  electromagnetic follow-up of ground-based gravitational wave detections
  of neutron star and black hole mergers. We describe this possibility
  for OpTIIX, an ISS technology demonstration of a 1.5 m diffraction
  limited optical telescope assembled in space, and ISS-Lobster, a
  wide-field imaging X-ray telescope now under study as a potential
  NASA mission. Both telescopes will be mounted on pointing platforms,
  allowing rapid positioning to the source of a gravitational wave
  event. Electromagnetic follow-up rates of several per year appear
  likely, offering a wealth of complementary science on the mergers of
  black holes and neutron stars.

Title: Sorptive fractionation of organic matter and formation of
    organo-hydroxy-aluminum complexes during litter biodegradation in
    the presence of gibbsite
Authors: Heckman, K.; Grandy, A. S.; Gao, X.; Keiluweit, M.; Wickings,
   K.; Carpenter, K.; Chorover, J.; Rasmussen, C.
Bibcode: 2013GeCoA.121..667H
Altcode:
  Solid and aqueous phase Al species are recognized to affect organic
  matter (OM) stabilization in forest soils. However, little is known
  about the dynamics of formation, composition and dissolution of
  organo-Al hydroxide complexes in microbially-active soil systems, where
  plant litter is subject to microbial decomposition in close proximity
  to mineral weathering reactions. We incubated gibbsite-quartz mineral
  mixtures in the presence of forest floor material inoculated with
  a native microbial consortium for periods of 5, 60 and 154 days. At
  each time step, samples were density separated into light (&lt;1.6
  g cm<SUP>-3</SUP>), intermediate (1.6-2.0 g cm<SUP>-3</SUP>), and
  heavy (&gt;2.0 g cm<SUP>-3</SUP>) fractions. The light fraction was
  mainly comprised of particulate organic matter, while the intermediate
  and heavy density fractions contained moderate and large amounts of
  Al-minerals, respectively. Multi-method interrogation of the fractions
  indicated the intermediate and heavy fractions differed both in mineral
  structure and organic compound composition. X-ray diffraction analysis
  and SEM/EDS of the mineral component of the intermediate fractions
  indicated some alteration of the original gibbsite structure into
  less crystalline Al hydroxide and possibly proto-imogolite species,
  whereas alteration of the gibbsite structure was not evident in the
  heavy fraction. DRIFT, Py-GC/MS and STXM/NEXAFS results all showed that
  intermediate fractions were composed mostly of lignin-derived compounds,
  phenolics, and polysaccharides. Heavy fraction organics were dominated
  by polysaccharides, and were enriched in proteins, N-bearing compounds,
  and lipids. The source of organics appeared to differ between the
  intermediate and heavy fractions. Heavy fractions were enriched
  in <SUP>13</SUP>C with lower C/N ratios relative to intermediate
  fractions, suggesting a microbial origin. The observed differential
  fractionation of organics among hydroxy-Al mineral types suggests that
  microbial activity superimposed with abiotic mineral-surface-mediated
  fractionation leads to strong density differentiation of organo-mineral
  complex composition even over the short time scales probed in these
  incubation experiments. The data highlight the strong interdependency
  of mineral transformation, microbial community activity, and organic
  matter stabilization during biodegradation.

Title: Tracing Magnetic "Active Regions" in Non-Coronal and Hybrid
    Cool Giants
Authors: Airapetian, Vladimir; Carpenter, K. G.
Bibcode: 2013giec.conf10305A
Altcode:
  FUSE and HST/STIS and GHRS observations of a number of non-coronal
  and hybrid giants reveal dynamics processes in their atmospheres. The
  observed variations in the fluxes, non-thermal broadening, and shifts of
  selected UV chromospheric emission lines provide a powerful diagnostic
  tool to characterize the total unsigned magnetic flux and its rotational
  modulation in cool giant stars, as well as the energy dissipation and
  momentum deposition in their atmospheres. We utilize a new empirical
  method, based on our numerical model of Alfvén wave-driven winds
  from evolved stars, to detect and characterize the signatures of the
  rotational modulation of magnetic "active regions" in two evolved
  giant stars, representative of both hybrid and non-coronal (K5 III)
  stars. Specifically, we derive the properties of chromospheric motions
  and heating rates at two or more epochs for each star. We use archival
  FUSE, HST/GHRS and HST/STIS observations to address a fundamental
  question in the evolution of magnetic dynamos in late-type giant stars,
  namely: what is the inter-relationship between chromospheric turbulence,
  magnetic flux, and the wind properties in cool, evolved stars?

Title: The Role of Alfvén Waves in Atmospheric Dynamics of
    Non-Coronal, Hybrid and Coronal Giants
Authors: Airapetian, Vladimir; Carpenter, K. G.; Evans, R. M.
Bibcode: 2013giec.conf30102A
Altcode:
  In this talk, we discuss the properties of atmospheric heating and
  wind dynamics from non-coronal, hybrid and coronal giants described by
  an Alfvén-wave driven model of stellar atmospheres. Specifically, we
  present the results of numerical simulations of winds from non-coronal
  and hybrid evolved giant stars using a fully nonlinear, time-dependent
  2.5-dimensional magnetohydrodynamic (MHD) code. This study extends our
  previous fully nonlinear MHD wind simulations to include a broadband
  frequency spectrum of Alfvén waves that drive winds from red giant
  stars. We discuss four Alfven wind models that cover the whole range of
  the Alfvén wave frequency spectrum to characterize the role of freely
  propagated and reflected Alfvén waves in the gravitationally stratified
  atmosphere of a late-type giant star. Our simulations demonstrate that,
  unlike linear Alfvén wave-driven wind models, a stellar wind model
  based on plasma acceleration due to broadband non-linear Alfvén waves
  can consistently reproduce the wide range of radial velocity profiles
  of the winds, their terminal velocities, and the observed mass loss
  rates observed in non-coronal and hybrid giants. We also present the
  recent results of simulations of the thermodynamics and dynamics of
  the atmosphere of a magnetically active coronal giant, β Ceti, by
  applying a 3D MHD code, BATRUS, that incorporates a self-consistent
  treatment of energy dissipation due Alfvén wave turbulence, thermal
  conduction and radiative cooling terms.

Title: Signatures of Rotational Modulation of Magnetic "Active
    Regions" in Hybrid and Non-coronal Cool Giant Stars
Authors: Carpenter, Kenneth G.; Airapetian, V.
Bibcode: 2013AAS...22211614C
Altcode:
  Observations of the variations in the fluxes, non-thermal broadening,
  and shifts of selected UV chromospheric emission lines provide a
  powerful diagnostic tool to characterize the total unsigned magnetic
  flux and its rotational modulation in cool giant stars, as well as the
  energy dissipation and momentum deposition in their atmospheres. We
  utilize a new empirical method, based on our 2.5D MHD model of Alfvén
  wave-driven winds from evolved stars, to detect and characterize the
  signatures of the rotational modulation of magnetic "active regions" in
  two evolved giant stars, representative of both hybrid and non-coronal
  (K5 III) stars. Specifically, we derive the properties of chromospheric
  motions and heating rates at two or more epochs for each star. We use
  archival HST/GHRS and HST/STIS observations to address a fundamental
  question in the evolution of magnetic dynamos in late-type giant stars,
  namely: what is the inter-relationship between chromospheric turbulence,
  magnetic flux, and the wind properties in cool, evolved stars?

Title: Mining the Advanced Spectral Library (ASTRAL): Characterizing
    Winds of Evolved M-Stars
Authors: Nielsen, Krister E.; Carpenter, K. G.; Kober, G. V.; Cheng,
   K.; Ayres, T. R.; Harper, G.
Bibcode: 2013AAS...22135102N
Altcode:
  The HST/STIS treasury program Advanced Spectral Library (ASTRAL)
  enables investigations of the character and dynamics of the wind and
  chromosphere of cool stars, using high quality spectral data. This
  paper present the analysis of the outflowing winds of the M3.4 giant
  Gamma Cru and the M2Iab supergiant Alpha Ori. The outer atmospheres
  of these objects show strong evidence for significant inhomogeneity
  in their thermal and kinematic structure, and are in general not
  well understood. The wind features are characterized by a strong
  chromospheric emission suppressed by a overlying wind absorption,
  for many transitions producing a double peak feature. The relative
  strengths and wavelength shifts between the absorption and emission
  components of the lines reflect the acceleration of the wind from the
  base of the chromosphere, as the self-absorption is due to the overlying
  wind absorption, whose velocity relative to the chromosphere varies
  with height and thus line opacity. The wind profiles are sensitive to
  the wind opacity, turbulence and flow velocity, and hence favorable
  to analyze with the Sobolev source function with Exact Integration of
  the transfer equation (SEI) code. This paper will show a velocity and
  intensity analysis of the wind profiles and modeling with the SEI code
  to derive an improved set of wind parameters, primarily, for Gamma Cru.

Title: Mining the Advanced Spectral Library (ASTRAL): Fluorescence
    in Evolved M-Stars
Authors: Carpenter, Kenneth G.; Nielsen, K. E.; Kober, G. V.; Cheng,
   K.; Ayres, T. R.; Wahlgren, G. M.; Harper, G.
Bibcode: 2013AAS...22135101C
Altcode:
  The "Advanced Spectral Library (ASTRAL) Project: Cool Stars" (PI =
  T. Ayres) is an HST Cycle 18 Treasury Program designed to collect
  a definitive set of representative, high-resolution ( 46,000 in the
  FUV up to ~1700 Å, 30,000 for 1700-2150 Å, and 114,000 &gt;2150 Å)
  and high signal/noise (S/N&gt;100) UV spectra of eight F-M evolved
  cool stars. These extremely high-quality STIS UV echelle spectra are
  available from the HST archive and through the University of Colorado
  (http://casa.colorado.edu ayres/ASTRAL/) and will enable investigations
  of a broad range of problems -- stellar, interstellar, and beyond -- for
  many years. In this paper, we use the very rich emission-line spectra
  of the two evolved M stars in the sample, the M3.4 giant Gamma Crucis
  (GaCrux) and the M2Iab supergiant Alpha Orionis (Betelgeuse), to study
  the fluorescence processes operating in their outer atmospheres. We
  summarize the pumping transitions and fluorescent line products known
  on the basis of previous work (e.g. Carpenter 1988 and references
  therein) and newly identified in our current, on-going analysis and
  provide some comments on their implications for the structure of the
  outer atmospheres of these stars.

Title: Using the ISS as a testbed to prepare for the next generation
    of space-based telescopes
Authors: Postman, Marc; Sparks, William B.; Liu, Fengchuan; Ess, Kim;
   Green, Joseph; Carpenter, Kenneth G.; Thronson, Harley; Goullioud,
   Renaud
Bibcode: 2012SPIE.8442E..1TP
Altcode:
  The infrastructure available on the ISS provides a unique opportunity
  to develop the technologies necessary to assemble large space
  telescopes. Assembling telescopes in space is a game-changing approach
  to space astronomy. Using the ISS as a testbed enables a concentration
  of resources on reducing the technical risks associated with integrating
  the technologies, such as laser metrology and wavefront sensing and
  control (WFS&amp;C), with the robotic assembly of major components
  including very light-weight primary and secondary mirrors and the
  alignment of the optical elements to a diffraction-limited optical
  system in space. The capability to assemble the optical system and
  remove and replace components via the existing ISS robotic systems
  such as the Special Purpose Dexterous Manipulator (SPDM), or by the
  ISS Flight Crew, allows for future experimentation as well as repair if
  necessary. In 2015, first light will be obtained by the Optical Testbed
  and Integration on ISS eXperiment (OpTIIX), a small 1.5-meter optical
  telescope assembled on the ISS. The primary objectives of OpTIIX include
  demonstrating telescope assembly technologies and end-to-end optical
  system technologies that will advance future large optical telescopes.

Title: Commission 29: Stellar Spectra
Authors: Piskunov, Nikolai; Cunha, Katia; Parthasarathy, Mudumba; Aoki,
   Wako; Asplund, Martin; Bohlender, David; Carpenter, Kenneth; Melendez,
   Jorge; Rossi, Silvia; Smith, Verne; Soderblom, David; Wahlgren, Glenn
Bibcode: 2012IAUTA..28..157P
Altcode:
  Commission 29 consists of members of the International Astronomical
  Union carrying out theoretical and observational studies of stars
  using spectroscopy, developing instrumentation for spectroscopy and
  producing and collecting data for interpretation of spectra.

Title: Harnessing the Power of NASA's Kepler Mission for Understanding
    Stellar Activity and Enhancing Planet Discovery
Authors: Bastien, Fabienne A.; Stassun, K. G.; Pepper, J.; Walkowicz,
   L.; Basri, G.; Carpenter, K. G.
Bibcode: 2012AAS...21934504B
Altcode:
  The magnetic activity of stars, which often manifests itself in the
  form of starspots, can induce short-timescale photometric variability,
  thereby adding to the difficulty of detecting planets, particularly
  those in the Earth mass range. Indeed, photometric "noise” caused
  by stellar magnetic activity can preclude the detection of the tiny
  transit signature that a planet like ours would produce. Hence, in order
  to successfully detect Earth-like planets via the transit method, the
  exoplanet community needs a way characterize the photometric stability
  of a star in advance. The goal of our project is to empirically relate
  chromospheric activity and photometric variability for a large sample
  of stars, spanning a range of stellar masses and evolutionary states,
  in order to develop an index that is predictive of stellar photometric
  variability. The inclusion of stars with a range of known rotation
  periods, as well as subgiants, giants, and Kepler asteroseismology
  targets, will allow us to more finely examine the relationship
  between a star's age and its magnetic activity. This work will aid
  in a fundamental understanding of the physics of magnetic activity
  in solar-type stars. We acknowledge support through NSF PAARE grant
  AST-0849736.

Title: The Amazing COS FUV (1320 - 1460 Å) Spectrum of λ Vel
    (K4Ib-II)<SUP>1</SUP>
Authors: Carpenter, K. G.; Ayres, T.; Brown, A.; Harper, G. M.;
   Wahlgren, G. M.
Bibcode: 2011ASPC..448.1083C
Altcode: 2011csss...16.1083C
  The FUV spectrum (1320-1460 Å) of the K4 Ib-II supergiant λ Vel
  was observed with the Cosmic Origins Spectrograph (COS) on HST, as
  part of the Ayres and Redfield Cycle 17 SNAP program "SNAPing Coronal
  Iron." This spectrum covers a region not previously recorded in λ
  Vel at high resolution and, in a mere 20 minutes of exposure, reveals
  an amazing treasure trove of information. It shows a wide variety of
  strong emission lines and multiple absorption lines, superposed on a
  bright chromospheric continuum, with contributions from both atomic
  and molecular species. These features provide diagnostics of the
  chromosphere and wind of the star, and by comparison with spectra of
  stars of similar T<SUB>eff</SUB> and/or g<SUB>eff</SUB>, will improve
  our knowledge of the heating processes in the chromospheres and the
  forces driving the stellar wind in cool evolved stars. We present
  the details of this spectrum, in comparison with stars of similar
  temperature or luminosity, and discuss our initial interpretation of
  the data.

Title: The Stellar Imager (SI) - A Mission to Resolve Stellar
    Surfaces, Interiors, and Magnetic Activity
Authors: Christensen-Dalsgaard, Jørgen; Carpenter, Kenneth G.;
   Schrijver, Carolus J.; Karovska, Margarita; Si Team
Bibcode: 2011JPhCS.271a2085C
Altcode:
  The Stellar Imager (SI) is a space-based, UV/Optical Interferometer
  (UVOI) designed to enable 0.1 milli-arcsecond (mas) spectral imaging
  of stellar surfaces and of the Universe in general. It will also probe
  via asteroseismology flows and structures in stellar interiors. SI
  will enable the development and testing of a predictive dynamo model
  for the Sun, by observing patterns of surface activity and imaging
  of the structure and differential rotation of stellar interiors in
  a population study of Sun-like stars to determine the dependence of
  dynamo action on mass, internal structure and flows, and time. SI's
  science focuses on the role of magnetism in the Universe and will
  revolutionize our understanding of the formation of planetary systems,
  of the habitability and climatology of distant planets, and of many
  magneto-hydrodynamically controlled processes in the Universe. SI
  is a "Landmark/Discovery Mission" in the 2005 Heliophysics Roadmap,
  an implementation of the UVOI in the 2006 Astrophysics Strategic Plan,
  and a NASA Vision Mission ("NASA Space Science Vision Missions" (2008),
  ed. M. Allen). We present here the science goals of the SI Mission,
  a mission architecture that could meet those goals, and the technology
  development needed to enable this mission. Additional information on
  SI can be found at: http://hires.gsfc.nasa.gov/si/.

Title: λ Vel (K4 Ib-II): Fluorescence on a PAR with Other Luminaries
Authors: Wahlgren, G. M.; Carpenter, K. G.; Ayres, T. R.; Brown, A.;
   Harper, G. M.
Bibcode: 2011AAS...21715406W
Altcode: 2011BAAS...4315406W
  The ultraviolet spectral region of cool, luminous stars contains
  emission features that originate from fluorescent mechanisms via PAR
  (photo-excitation by accidental resonance). These mechanisms can account
  for numerous emission lines, downward transitions from upper energy
  levels pumped by strong transitions, such as H Ly-α, O I 1302, C II
  1335, and Mg II h&amp;k. A new, high S/N observation of the cool giant
  star λ Vel (K4 Ib-II) was obtained with the HST/COS instrument at a
  resolving power of R 20000 and covers the wavelength region from 132 nm
  to 147 nm. High-quality spectra (COS and GHRS) are now available from
  128 nm to 147 nm, and at 12 moderate and high resolution observations
  from the HST/GHRS, the latter covering approximately a third of the
  wavelength interval from 189 nm to 285 nm. Using these data, together
  with observations from FUSE and IUE, we investigate PAR processes in the
  spectra of Cr II and Fe II and make comparisons with other stars. The
  presence of additional atomic (O I, S I, and Cl I) and molecular (H2,
  CO) PAR processes in the spectrum of λ Vel is briefly discussed.

Title: The Chromospheric Structure and Wind of the K-Supergiant
    Lambda Velorum
Authors: Carpenter, Kenneth G.; Ayres, T. R.; Brown, A.; Harper,
   G. M.; Wahlgren, G. M.
Bibcode: 2011AAS...21715407C
Altcode: 2011BAAS...4315407C
  Recently, the 1326-1466 Å region of the FUV spectrum of the K4 Ib-II
  supergiant Lambda Vel was observed with the Cosmic Origins Spectrograph
  (COS) on HST, as part of the Ayres and Redfield Cycle 17 SNAP program
  "SNAPing Coronal Iron.” This spectrum covers a region not previously
  recorded in Lambda Vel at high resolution and, in a mere 20 minutes
  of exposure, reveals an amazing treasure trove of information. It
  shows a wide variety of strong atomic and molecular emission lines
  formed in the chromosphere and multiple atomic absorption lines
  formed in the stellar wind, both superposed on a bright chromospheric
  continuum. Further evidence of the stellar wind is seen in the P Cygni
  profiles presented by the C II (UV 1) lines near 1335 Å. We combine
  this COS data with archival GHRS spectra of other selected FUV and NUV
  regions to better characterize the outer atmospheric structure of the
  star and its massive, outflowing wind.

Title: Winds from Luminous Late-type Stars. II. Broadband Frequency
    Distribution of Alfvén Waves
Authors: Airapetian, V.; Carpenter, K. G.; Ofman, L.
Bibcode: 2010ApJ...723.1210A
Altcode: 2010arXiv1008.3955A
  We present the numerical simulations of winds from evolved giant
  stars using a fully nonlinear, time-dependent 2.5-dimensional
  magnetohydrodynamic (MHD) code. This study extends our previous fully
  nonlinear MHD wind simulations to include a broadband frequency spectrum
  of Alfvén waves that drive winds from red giant stars. We calculated
  four Alfvén wind models that cover the whole range of the Alfvén wave
  frequency spectrum to characterize the role of freely propagated and
  reflected Alfvén waves in the gravitationally stratified atmosphere
  of a late-type giant star. Our simulations demonstrate that, unlike
  linear Alfvén wave-driven wind models, a stellar wind model based
  on plasma acceleration due to broadband nonlinear Alfvén waves can
  consistently reproduce the wide range of observed radial velocity
  profiles of the winds, their terminal velocities, and the observed
  mass-loss rates. Comparison of the calculated mass-loss rates with the
  empirically determined mass-loss rate for α Tau suggests an anisotropic
  and time-dependent nature of stellar winds from evolved giants.

Title: Stellar Imager (SI): developing and testing a predictive
    dynamo model for the Sun by imaging other stars
Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska,
   Margarita; Kraemer, Steve; Lyon, Richard; Mozurkewich, David;
   Airapetian, Vladimir; Adams, John C.; Allen, Ronald J.; Brown, Alex;
   Bruhweiler, Fred; Conti, Alberto; Christensen-Dalsgaard, Joergen;
   Cranmer, Steve; Cuntz, Manfred; Danchi, William; Dupree, Andrea; Elvis,
   Martin; Evans, Nancy; Giampapa, Mark; Harper, Graham; Hartman, Kathy;
   Labeyrie, Antoine; Leitner, Jesse; Lillie, Chuck; Linsky, Jeffrey L.;
   Lo, Amy; Mighell, Ken; Miller, David; Noecker, Charlie; Parrish, Joe;
   Phillips, Jim; Rimmele, Thomas; Saar, Steve; Sasselov, Dimitar; Stahl,
   H. Philip; Stoneking, Eric; Strassmeier, Klaus; Walter, Frederick;
   Windhorst, Rogier; Woodgate, Bruce; Woodruff, Robert
Bibcode: 2010arXiv1011.5214C
Altcode:
  The Stellar Imager mission concept is a space-based UV/Optical
  interferometer designed to resolve surface magnetic activity and
  subsurface structure and flows of a population of Sun-like stars,
  in order to accelerate the development and validation of a predictive
  dynamo model for the Sun and enable accurate long-term forecasting of
  solar/stellar magnetic activity.

Title: Commission 29: Stellar Spectra
Authors: Piskunov, Nikolai; Cunha, Katia; Parthasarathy, Mudumba;
   Aoki, Wako; Asplund, Martin; Bohlender, David; Carpenter, Kenneth;
   Melendez, Jorge; Parthasarathy, Mudumba; Rossi, Silvia; Smith, Verne;
   Soderblom, David; Wahlgren, Glenn
Bibcode: 2010IAUTB..27..193P
Altcode:
  The business meeting was attended by 23 members of the Commission. The
  meeting started at 16:00 a short report of the activities during the
  triennium 2006-2009. The focus of the activities was the sharing
  of expertise between spectroscopic techniques in various areas of
  astronomical research. In particular, the progress in instrumentation,
  detectors, data reduction, data analysis and archiving. The second
  activity was the analysis of to IAU meeting proposals followed by
  recommendations for improvements and eventually support. The sponsored
  symposia included Sponsoring symposia The Ages of Stars and The Disk
  Galaxy Evolution in the Cosmological Context. The Commission was also
  disseminating information about the Commission activities and relevant
  meetings to the Commission members. In this respect the Commission
  web page is playing a crucial role.

Title: 2.5d Mhd Simulations Of Winds From Red Giants Stars: Broadband
    Alfvén Waves
Authors: Airapetian, Vladimir; Carpenter, K.; Ofman, L.
Bibcode: 2010AAS...21542703A
Altcode: 2010BAAS...42..342A
  We present the numerical simulations of winds from evolved giant
  stars using a fully non-linear, time dependent, 2.5-dimensional
  magnetohydrodynamic (MHD) code. This study extends our previous
  fully non-linear MHD wind simulations to the parameter space that
  describes winds from red giant stars. In the current version of this
  Alfvén wave driven model, a wind is driven by randomly generated
  low-frequency non-linear Alfvén waves in a broadband frequency
  range at the base of the wind. We simulate freely propagated and
  partially reflected Alfvén waves in the gravitationally stratified
  atmosphere of a late-type giant star, in a self-consistent manner,
  until a steady-state wind is formed. Our simulations demonstrate
  that, unlike linear Alfven wave-driven wind models, a stellar wind
  model based on plasma acceleration due to low frequency broad-band
  non-linear Alfvén waves, can consistently reproduce the observed radial
  velocity profiles of the winds, their terminal velocities, the turbulent
  broadening of UV lines emitted from those winds and the observed mass
  loss rates. We find that conversion of non-linear transverse Alfvén
  waves into longitudinal magnetosonic waves plays the major role in
  depositing momentum and energy into the stellar wind. The fitting of
  mass-loss rates from α Tau with the predicted rate suggests a highly
  anisotropic stellar wind in this evolved giant. The model also predicts
  a variation of the wind mass-loss rates on time scales of 1 month.

Title: The Stellar Commodity Market: Cu, Ag, And Au In The Sun And
    Solar-type Stars
Authors: Wahlgren, Glenn Michael; Carpenter, K. G.; Nave, G.
Bibcode: 2010AAS...21542705W
Altcode: 2010BAAS...42..343W
  The elements copper, silver and gold occupy the same column of the
  periodic table and share the property that their only stable isotopes
  are odd-numbered, which implies a need for hyperfine structure data when
  analyzing their spectral lines. A comparison of their solar photospheric
  abundances with the standard meteoritic element abundances shows that
  for two of them (Ag, Au) the differences are as large as or larger than
  the sum of the uncertainties. With some exceptions, the study of the
  chemical composition of most stars stops at the end of the iron group of
  elements. Heavier elements are typically not analyzed, often due to the
  lack of accurate atomic line data. While the post iron-group elements
  make a small contribution to the total abundance one can argue that,
  for many reasons, life on earth would not be the same without copper,
  silver and gold. <P />We first revisit the abundances of these elements
  in the solar photosphere, accounting for the revisions in atomic
  data since these elements were last analyzed in the photosphere. The
  hyperfine structure of Cu I and Ag I is included in our synthetic
  spectrum calculations. The spectra Cu I and Cu II are of current
  interest to us for the determination of hfs constants based on our
  new laboratory Fourier transform spectrometer data. We then determine
  the abundances for these elements in the high-resolution spectra
  for a sample of solar-like stars, obtained from on-line data bases,
  using synthetic spectrum techniques. The analysis aims to determine the
  abundance dispersion of these elements in solar-like stars in the solar
  neighborhood. Some of these stars are known to possess exo-planets,
  and the abundances of these elements will be correlated with host star
  metallicity. In general, we aim to encourage a more extensive use of
  the periodic table for stellar astrophysics.

Title: The Stellar Imager (SI) - A Mission to Resolve Stellar
    Surfaces, Interiors, and Magnetic Activity
Authors: Carpenter, K. G.; Schrijver, C. J.; Karovska, M.; Si Vision
   Mission Team
Bibcode: 2009ASPC..412...91C
Altcode:
  The Stellar Imager (SI) is a UV/Optical, Space-Based Interferometer
  designed to enable 0.1 milli-arcsecond (mas) spectral imaging of
  stellar surfaces and, via asteroseismology, stellar interiors and of
  the Universe in general. The ultra-sharp images of the Stellar Imager
  will revolutionize our view of many dynamic astrophysical processes
  by transforming point sources into extended sources, and snapshots
  into evolving views. SI's science focuses on the role of magnetism
  in the Universe, particularly on magnetic activity on the surfaces of
  stars like the Sun. SI's prime goal is to enable long-term forecasting
  of solar activity and the space weather that it drives. SI will also
  revolutionize our understanding of the formation of planetary systems,
  of the habitability and climatology of distant planets, and of many
  magneto-hydrodynamically controlled processes in the Universe. SI is
  included as a ``Flagship and Landmark Discovery Mission'' in the 2005
  NASA Sun Solar System Connection (SSSC) Roadmap and as a candidate
  for a ``Pathways to Life Observatory'' in the NASA Exploration of the
  Universe Division (EUD) Roadmap (May, 2005). In this paper we discuss
  the science goals and technology needs of, and the baseline design
  for, the SI Mission (http://hires.gsfc.nasa.gov/si/) and its ability
  to image the Biggest, Baddest, Coolest Stars.

Title: Balloon exoplanet nulling interferometer (BENI)
Authors: Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.;
   Vasudevan, Gopal; Ford, Holland; Petro, Larry; Herman, Jay; Rinehart,
   Stephen; Carpenter, Kenneth; Marzouk, Joe
Bibcode: 2009SPIE.7440E..1AL
Altcode: 2009SPIE.7440E..38L
  We evaluate the feasibility of a balloon-borne nulling interferometer to
  detect and characterize an exosolar planet and the surrounding debris
  disk. The existing instrument consists of a three-telescope Fizeau
  imaging interferometer with thre fast steering mirrors and three delay
  lines operating at 800 Hz for closed-loop control of wavefront errors
  and fine pointing. A compact visible nulling interferometer would be
  coupled to the imaging interferometer and in principle, allows deep
  starlight suppression. Atmospheric simulations of the environment
  above 100,000 feet show that balloonborne payloads are a possible
  path towards the direct detection and characterization of a limited
  set of exoplanets and debris disks. Furthermore, rapid development
  of lower cost balloon payloads provide a path towards advancement
  of NASA technology readiness levels for future space-based exoplanet
  missions. Discussed are the BENI mission and instrument, the balloon
  environment and the feasibility of such a balloon-borne mission.

Title: Stellar imager (SI): enhancements to the mission enabled by
    the constellation architecture (Ares I/Ares V)
Authors: Carpenter, Kenneth G.; Karovska, Margarita; Lyon, Richard G.;
   Mozurkewich, D.; Schrijver, Carolus
Bibcode: 2009SPIE.7436E..0AC
Altcode: 2009SPIE.7436E...9C
  Stellar Imager (SI) is a space-based, UV/Optical Interferometer (UVOI)
  with over 200x the resolution of HST. It will enable 0.1 milli-arcsec
  spectral imaging of stellar surfaces and the Universe in general
  and open an enormous new "discovery space" for astrophysics with its
  combination of high angular resolution, dynamic imaging, and spectral
  energy resolution. SI's goal is to study the role of magnetism in
  the Universe and revolutionize our understanding of: 1) Solar/Stellar
  Magnetic Activity and their impact on Space Weather, Planetary Climates,
  and Life, 2) Magnetic and Accretion Processes and their roles in the
  Origin &amp; Evolution of Structure and in the Transport of Matter
  throughout the Universe, 3) the close-in structure of Active Galactic
  Nuclei and their winds, and 4) Exo-Solar Planet Transits and Disks. SI
  is a "Landmark/Discovery Mission" in 2005 Heliophysics Roadmap and a
  candidate UVOI in the 2006 Astrophysics Strategic Plan and is targeted
  for launch in the mid-2020's. It is a NASA Vision Mission and has
  been recommended for further study in a 2008 NRC report on missions
  potentially enabled/enhanced by an Ares V launch. In this paper,
  we discuss the science goals and required capabilities of SI, the
  baseline architecture of the mission assuming launch on one or more
  Delta rockets, and then the potential significant enhancements to the
  SI science and mission architecture that would be made possible by a
  launch in the larger volume Ares V payload fairing, and by servicing
  options under consideration in the Constellation program.

Title: Transient Processes in the Atmosphere of α Tau
Authors: Airapetian, V.; Carpenter, K. G.; Ake, T.
Bibcode: 2009AIPC.1135..215A
Altcode:
  Far Ultraviolet Spectrograph Explorer (FUSE) spectra of UV emission
  lines observed in α Tau at two epochs separated by four months show
  dramatic differences in emission line fluxes and line shifts. This
  presents the first evidence of dynamic plasma heating in the active
  region of this cool giant star. We discuss these observations in terms
  of Alfven wave heating in magnetic loops.

Title: The Stellar Imager (SI) project: a deep space UV/Optical
    Interferometer (UVOI) to observe the Universe at 0.1 milli-arcsec
    angular resolution
Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska,
   Margarita
Bibcode: 2009Ap&SS.320..217C
Altcode: 2008Ap&SS.tmp...99C
  The Stellar Imager (SI) is a space-based, UV/Optical Interferometer
  (UVOI) designed to enable 0.1 milli-arcsecond (mas) spectral imaging
  of stellar surfaces and of the Universe in general. It will also probe
  via asteroseismology flows and structures in stellar interiors. SI’s
  science focuses on the role of magnetism in the Universe and will
  revolutionize our understanding of the formation of planetary systems,
  of the habitability and climatology of distant planets, and of many
  magneto-hydrodynamically controlled processes, such as accretion, in
  the Universe. The ultra-sharp images of SI will revolutionize our view
  of many dynamic astrophysical processes by transforming point sources
  into extended sources, and snapshots into evolving views. SI is a
  “Flagship and Landmark Discovery Mission” in the 2005 Heliophysics
  Roadmap and a potential implementation of the UVOI in the 2006 Science
  Program for NASA’s Astronomy and Physics Division. We present here
  the science goals of the SI Mission, a mission architecture that
  could meet those goals, and the technology development needed to
  enable this mission. Additional information on SI can be found at:
  http://hires.gsfc.nasa.gov/si/

Title: Technology Development for Future Sparse Aperture Telescopes
    and Interferometers in Space
Authors: Carpenter, Kenneth G.; Gendreau, Keith; Leitner, Jesse; Lyon,
   Richard; Stoneking, Eric; Stahl, H. Philip; Parrish, Joe; Schrijver,
   Carolus J.; Woodruff, Robert; Lillie, Chuck; Lo, Amy; Mozurkewich,
   David; Labeyrie, Antoine; Miller, David; Mighell, Ken; Karovska,
   Margarita; Phillips, James; Allen, Ronald J.; Cash, Webster
Bibcode: 2009astro2010T..47C
Altcode:
  No abstract at ADS

Title: Luciola hypertelescope space observatory: versatile, upgradable
    high-resolution imaging, from stars to deep-field cosmology
Authors: Labeyrie, Antoine; Le Coroller, Hervé; Dejonghe, Julien;
   Lardière, Olivier; Aime, Claude; Dohlen, Kjetil; Mourard, Denis;
   Lyon, Richard; Carpenter, Kenneth G.
Bibcode: 2009ExA....23..463L
Altcode: 2008ExA...tmp...48L
  Luciola is a large (1 km) “multi-aperture densified-pupil imaging
  interferometer”, or “hypertelescope” employing many small
  apertures, rather than a few large ones, for obtaining direct snapshot
  images with a high information content. A diluted collector mirror,
  deployed in space as a flotilla of small mirrors, focuses a sky image
  which is exploited by several beam-combiner spaceships. Each contains a
  “pupil densifier” micro-lens array to avoid the diffractive spread
  and image attenuation caused by the small sub-apertures. The elucidation
  of hypertelescope imaging properties during the last decade has shown
  that many small apertures tend to be far more efficient, regarding the
  science yield, than a few large ones providing a comparable collecting
  area. For similar underlying physical reasons, radio-astronomy has
  also evolved in the direction of many-antenna systems such as the
  proposed Low Frequency Array having “hundreds of thousands of
  individual receivers”. With its high limiting magnitude, reaching
  the m <SUB>v</SUB> = 30 limit of HST when 100 collectors of 25 cm will
  match its collecting area, high-resolution direct imaging in multiple
  channels, broad spectral coverage from the 1,200 Å ultra-violet to
  the 20 μm infra-red, apodization, coronagraphic and spectroscopic
  capabilities, the proposed hypertelescope observatory addresses very
  broad and innovative science covering different areas of ESA’s Cosmic
  Vision program. In the initial phase, a focal spacecraft covering
  the UV to near IR spectral range of EMCCD photon-counting cameras
  (currently 200 to 1,000 nm), will image details on the surface of
  many stars, as well as their environment, including multiple stars
  and clusters. Spectra will be obtained for each resel. It will also
  image neutron star, black-hole and micro-quasar candidates, as well as
  active galactic nuclei, quasars, gravitational lenses, and other Cosmic
  Vision targets observable with the initial modest crowding limit. With
  subsequent upgrade missions, the spectral coverage can be extended
  from 120 nm to 20 μm, using four detectors carried by two to four
  focal spacecraft. The number of collector mirrors in the flotilla can
  also be increased from 12 to 100 and possibly 1,000. The imaging and
  spectroscopy of habitable exoplanets in the mid infra-red then becomes
  feasible once the collecting area reaches 6 m<SUP>2</SUP>, using a
  specialized mid infra-red focal spacecraft. Calculations (Boccaletti
  et al., Icarus 145, 628-636, 2000) have shown that hypertelescope
  coronagraphy has unequalled sensitivity for detecting, at mid infra-red
  wavelengths, faint exoplanets within the exo-zodiacal glare. Later
  upgrades will enable the more difficult imaging and spectroscopy of
  these faint objects at visible wavelengths, using refined techniques
  of adaptive coronagraphy (Labeyrie and Le Coroller 2004). Together,
  the infra-red and visible spectral data carry rich information on
  the possible presence of life. The close environment of the central
  black-hole in the Milky Way will be imageable with unprecedented detail
  in the near infra-red. Cosmological imaging of remote galaxies at the
  limit of the known universe is also expected, from the ultra-violet
  to the near infra-red, following the first upgrade, and with greatly
  increasing sensitivity through successive upgrades. These areas will
  indeed greatly benefit from the upgrades, in terms of dynamic range,
  limiting complexity of the objects to be imaged, size of the elementary
  “Direct Imaging Field”, and limiting magnitude, approaching
  that of an 8-m space telescope when 1,000 apertures of 25 cm are
  installed. Similar gains will occur for addressing fundamental problems
  in physics and cosmology, particularly when observing neutron stars
  and black holes, single or binary, including the giant black holes,
  with accretion disks and jets, in active galactic nuclei beyond the
  Milky Way. Gravitational lensing and micro-lensing patterns, including
  time-variable patterns and perhaps millisecond lensing flashes which may
  be beamed by diffraction from sub-stellar masses at sub-parsec distances
  (Labeyrie, Astron Astrophys 284, 689, 1994), will also be observable
  initially in the favourable cases, and upgrades will greatly improve the
  number of observable objects. The observability of gravitational waves
  emitted by binary lensing masses, in the form of modulated lensing
  patterns, is a debated issue (Ragazzoni et al., MNRAS 345, 100-110,
  2003) but will also become addressable observationally. The technology
  readiness of Luciola approaches levels where low-orbit testing and
  stepwise implementation will become feasible in the 2015-2025 time
  frame. For the following decades beyond 2020, once accurate formation
  flying techniques will be mastered, much larger hypertelescopes such
  as the proposed 100 km Exo-Earth Imager and the 100,000 km Neutron
  Star Imager should also become feasible. Luciola is therefore also
  seen as a precursor toward such very powerful instruments.

Title: Heavy Elements and Cool Stars
Authors: Wahlgren, Glenn M.; Carpenter, Kenneth G.; Norris, Ryan P.
Bibcode: 2009AIPC.1094..892W
Altcode: 2009csss...15..892W
  We report on progress in the analysis of high-resolution near-IR
  spectra of α Orionis (M2 Iab) and other cool, luminous stars. Using
  synthetic spectrum techniques, we search for atomic absorption lines
  in the stellar spectra and evaluate the available line parameter data
  for use in our abundance analyses. Our study concentrates on the post
  iron-group elements copper through zirconium as a means of investigating
  the slow neutron-capture process of nucleosynthesis in massive stars
  and the mechanisms that transport recently processed material up into
  the photospheric region. We discuss problems with the atomic data and
  model atmospheres that need to be addressed before theoretically derived
  elemental abundances from pre-supernova nucleosynthesis calculations
  can be tested by comparison with abundances determined from observations
  of cool, massive stars.

Title: UV, IR, and mm Studies of CO Surrounding the Red Supergiant
    α Orionis (M2 Iab)
Authors: Harper, Graham M.; Carpenter, Kenneth G.; Ryde, Nils; Smith,
   Nathan; Brown, Joanna; Brown, Alexander; Hinkle, Kenneth H.
Bibcode: 2009AIPC.1094..868H
Altcode: 2009csss...15..868H
  Carbon monoxide has been detected in Betelgeuse's ultraviolet
  (electronic), infrared (vibrational), and mm-radio (rotational) spectra,
  but its spatial distribution has remained elusive. We have obtained new
  mm-radio interferometry (CARMA), infrared spatially-resolved spectra
  (Phoenix/Gemini-South), and we have performed non-LTE simulations to
  help establish the spatial location of the S1 (V = 10 km/s) and S2 (V =
  17 km/s) CO shells. The strong CO Fourth-Positive ultraviolet scattering
  signature is apparent in the HST GHRS G140L spectrum and the S1 and
  S2 shells account for much of the UV opacity. Phoenix spectra reveal
  that the low velocity S1 shell is present at 1.5 arcsec West of the
  star and extends out to ~4 arcsec, and its mm-radio emission appears to
  originate within an 6 arcsec radius. The interpretation of the S2 shell
  is less clear. The Phoenix spectra tentatively suggest that the S2 shell
  extends to ~7 arcsec. The CARMA channel maps show an additional strong
  narrow emission component 5 arcsec from the star, but the spectra do not
  show all the expected S1 and S2 signatures. Future CARMA observations
  should help to disentangle the signature of the S1 and S2 shells.

Title: The Atmospheric Dynamics of α Tau (K5 III)-Clues to
    Understanding the Magnetic Dynamo in Late-Type Giant Stars
Authors: Carpenter, Kenneth G.; Airapetian, Vladimir
Bibcode: 2009AIPC.1094..712C
Altcode: 2009csss...15..712C
  Using HST/GHRS, HST/STIS and FUSE archival data for α Tau and the
  CHIANTI spectroscopic code, we have derived line shifts, volumetric
  emission measures, and plasma density estimates, and calculated
  filling factors for a number of UV lines forming between 10,000 K
  and 300,000 K in the outer atmosphere of this red giant star. The
  data suggest the presence of low-temperature extended regions and
  high-temperature compact regions, associated with magnetically open
  and closed structures in the stellar atmosphere, respectively. The
  signatures of UV lines from α Tau can be consistently understood
  via a model of upward-traveling Alfvén waves in a gravitationally
  stratified atmosphere. These waves cause nonthermal broadening in UV
  lines due to unresolved wave motions and downward plasma motions in
  compact magnetic loops heated by resonant Alfvén wave heating.

Title: Commission 29: Stellar Spectra
Authors: Parthasarathy, Mudumba; Piskunov, Nikolai E.; Sneden,
   Christopher; Carpenter, Kenneth G.; Castelli, Fiorella; Cunha, Katia;
   Eenens, Phillippe R. J.; Hubeny, Ivan; Rossi, Silvia; Takada-Hidai,
   Masahide; Wahlgren, Glenn M.; Weiss, Werner W.
Bibcode: 2009IAUTA..27..209P
Altcode:
  The members of IAU Commission 29 Stellar Spectra are actively
  engaged in the quantitative analysis of spectra of various types
  of stars. With large and medium size telescopes equipped with high
  resolution spectrographs LTE and Non-LTE analysis of spectra of all
  types stars are being carried out. Spectra of stars in our Galaxy,
  in globular and open clusters, stars in LMC and SMC and in nearby
  galaxies are being studied. Accurate chemical composition analysis
  of various types of stars has been carried out during the past three
  years. Now the analysis of stellar spectra covers the wavelength range
  from X-ray region to IR and sub-millimeter range. Recently stellar
  spectra are being analysed using time-dependent, 3D, hydrodynamical
  model atmospheres to derive accurate stellar abundances.

Title: Mass Transport Processes and their Roles in the Formation,
    Structure, and Evolution of Stars and Stellar Systems
Authors: Carpenter, Kenneth G.; Karvovska, Margarita; Schrijver,
   Carolus J.; Grady, Carol A.; Allen, Ronald J.; Brown, Alexander;
   Cranmer, Steven R.; Dupree, Andrea K.; Evans, Nancy R.; Guinan,
   Edward F.; Harper, Graham; Labeyrie, Antoine; Linsky, Jeffrey;
   Peters, Geraldine J.; Roberge, Aki; Saar, Steven H.; Sonneborn,
   George; Walter, Frederick M.
Bibcode: 2009astro2010S..40C
Altcode: 2009arXiv0903.2433C
  We summarize some of the compelling new scientific opportunities
  for understanding stars and stellar systems that can be enabled
  by sub-mas angular resolution, UV/Optical spectral imaging
  observations, which can reveal the details of the many dynamic
  processes (e.g., variable magnetic fields, accretion, convection,
  shocks, pulsations, winds, and jets) that affect their formation,
  structure, and evolution. These observations can only be provided
  by long-baseline interferometers or sparse aperture telescopes in
  space, since the aperture diameters required are in excess of 500 m -
  a regime in which monolithic or segmented designs are not and will
  not be feasible - and since they require observations at wavelengths
  (UV) not accessible from the ground. Two mission concepts which could
  provide these invaluable observations are NASA's Stellar Imager (SI;
  http://hires.gsfc.nasa.gov/si/) interferometer and ESA's Luciola
  sparse aperture hypertelescope, which each could resolve hundreds
  of stars and stellar systems. These observatories will also open an
  immense new discovery space for astrophysical research in general and,
  in particular, for Active Galactic Nuclei (Kraemer et al. Decadal
  Survey Science Whitepaper). The technology developments needed for
  these missions are challenging, but eminently feasible (Carpenter et
  al. Decadal Survey Technology Whitepaper) with a reasonable investment
  over the next decade to enable flight in the 2025+ timeframe. That
  investment would enable tremendous gains in our understanding of the
  individual stars and stellar systems that are the building blocks of our
  Universe and which serve as the hosts for life throughout the Cosmos.

Title: Active Galactic Nuclei and their role in Galaxy Formation
    and Evolution
Authors: Kraemer, Steve; Windhorst, Rogier; Carpenter, Kenneth G.;
   Crenshaw, Mike; Elvis, Martin; Karovska, Margarita
Bibcode: 2009astro2010S.162K
Altcode: 2009arXiv0904.3875K
  There are several key open questions as to the nature and origin of AGN
  including: 1) what initiates the active phase, 2) the duration of the
  active phase, and 3) the effect of the AGN on the host galaxy. Critical
  new insights to these can be achieved by probing the central regions
  of AGN with sub-mas angular resolution at UV/optical wavelengths. In
  particular, such observations would enable us to constrain the
  energetics of the AGN "feedback" mechanism, which is critical for
  understanding the role of AGN in galaxy formation and evolution. These
  observations can only be obtained by long-baseline interferometers
  or sparse aperture telescopes in space, since the aperture diameters
  required are in excess of 500 m - a regime in which monolithic or
  segmented designs are not and will not be feasible and because these
  observations require the detection of faint emission near the bright
  unresolved continuum source, which is impossible from the ground,
  even with adaptive optics. Two mission concepts which could provide
  these invaluable observations are NASA's Stellar Imager (SI; Carpenter
  et al. 2008 &amp; http://hires.gsfc.nasa.gov/si/) interferometer and
  ESA's Luciola (Labeyrie 2008) sparse aperture hypertelescope.

Title: Stellar Imager (SI) - Observing the Universe in High Definition
Authors: Carpenter, Kenneth G.; Karovska, M.; Schrijver, C. J.;
   SI Development Team
Bibcode: 2009AAS...21345113C
Altcode: 2009BAAS...41..346C
  Stellar Imager (http://hires.gsfc.nasa.gov/si/) is a space-based,
  UV/Optical Interferometer (UVOI) with over 200x HST's resolution. It
  will enable 0.1 milli-arcsec spectral imaging of stellar surfaces and
  the Universe in general and open an enormous new "discovery space"
  for Astrophysics with its combination of high angular resolution,
  dynamic imaging, and spectral energy resolution. SI's goal is to
  study the role of magnetism in the Universe and revolutionize our
  understanding of: 1) Solar/Stellar Magnetic Activity and their
  impact on Space Weather, Planetary Climates, and Life, 2) Magnetic
  and Accretion Processes and their roles in the Origin and Evolution
  of Structure and in the Transport of Matter throughout the Universe,
  3) the close-in structure of Active Galactic Nuclei, and 4) Exo-Solar
  Planet Transits and Disks. The SI mission is targeted for the mid
  2020's - thus significant technology development in the upcoming decade
  is critical to enabling it and future space-based sparse aperture
  telescope and distributed spacecraft missions. The key technology
  needs include: 1) precision formation flying of many spacecraft,
  2) precision metrology over km-scales, 3) closed-loop control of
  many-element, sparse optical arrays, 4) staged-control systems with
  very high dynamic ranges (nm to km-scale). It is critical that the
  importance of timely development of these capabilities is called
  out in the upcoming Astrophysics and Heliophysics Decadal Surveys,
  to enable the flight of such missions in the following decade. SI
  is a "Landmark/Discovery Mission" in the 2005 Heliophysics Roadmap
  and a candidate UVOI in the 2006 Astrophysics Strategic Plan. It is
  a NASA Vision Mission ("NASA Space Science Vision Missions" (2008),
  ed. M. Allen) and has also been recommended for further study in the
  2008 NRC interim report on missions potentially enabled or enhanced
  by an Ares V launch, although an incrementally-deployed version could
  be launched using smaller rockets.

Title: Exoplanet Characterization and the Search for Life
Authors: Kasting, James; Traub, W.; Roberge, A.; Leger, A.; Schwartz,
   A.; Wootten, A.; Vosteen, A.; Lo, A.; Brack, A.; Tanner, A.; Coustenis,
   A.; Lane, B.; Oppenheimer, B.; Mennesson, B.; Lopez, B.; Grillmair, C.;
   Beichman, C.; Cockell, C.; Hanot, C.; McCarthy, C.; Stark, C.; Marois,
   C.; Aime, C.; Angerhausen, D.; Montes, D.; Wilner, D.; Defrere, D.;
   Mourard, D.; Lin, D.; Kite, E.; Chassefiere, E.; Malbet, F.; Tian,
   F.; Westall, F.; Illingworth, G.; Vasisht, G.; Serabyn, G.; Marcy, G.;
   Bryden, G.; White, G.; Laughlin, G.; Torres, G.; Hammel, H.; Ferguson,
   H.; Shibai, H.; Rottgering, H.; Surdej, J.; Wiseman, J.; Ge, J.; Bally,
   J.; Krist, J.; Monnier, J.; Trauger, J.; Horner, J.; Catanzarite, J.;
   Harrington, J.; Nishikawa, J.; Stapelfeldt, K.; von Braun, K.; Biazzo,
   K.; Carpenter, K.; Balasubramanian, K.; Kaltenegger, L.; Postman, M.;
   Spaans, M.; Turnbull, M.; Levine, M.; Burchell, M.; Ealey, M.; Kuchner,
   M.; Marley, M.; Dominik, M.; Mountain, M.; Kenworthy, M.; Muterspaugh,
   M.; Shao, M.; Zhao, M.; Tamura, M.; Kasdin, N.; Haghighipour, N.;
   Kiang, N.; Elias, N.; Woolf, N.; Mason, N.; Absil, O.; Guyon, O.;
   Lay, O.; Borde, P.; Fouque, P.; Kalas, P.; Lowrance, P.; Plavchan,
   P.; Hinz, P.; Kervella, P.; Chen, P.; Akeson, R.; Soummer, R.; Waters,
   R.; Barry, R.; Kendrick, R.; Brown, R.; Vanderbei, R.; Woodruff, R.;
   Danner, R.; Allen, R.; Polidan, R.; Seager, S.; MacPhee, S.; Hosseini,
   S.; Metchev, S.; Kafka, S.; Ridgway, S.; Rinehart, S.; Unwin, S.;
   Shaklan, S.; ten Brummelaar, T.; Mazeh, T.; Meadows, V.; Weiss, W.;
   Danchi, W.; Ip, W.; Rabbia, Y.
Bibcode: 2009astro2010S.151K
Altcode: 2009arXiv0911.2936K
  Over 300 extrasolar planets (exoplanets) have been detected orbiting
  nearby stars. We now hope to conduct a census of all planets around
  nearby stars and to characterize their atmospheres and surfaces with
  spectroscopy. Rocky planets within their star's habitable zones have
  the highest priority, as these have the potential to harbor life. Our
  science goal is to find and characterize all nearby exoplanets; this
  requires that we measure the mass, orbit, and spectroscopic signature of
  each one at visible and infrared wavelengths. The techniques for doing
  this are at hand today. Within the decade we could answer long-standing
  questions about the evolution and nature of other planetary systems,
  and we could search for clues as to whether life exists elsewhere in
  our galactic neighborhood.

Title: Stellar Imager: wavefront control
Authors: Lyon, Richard G.; Carpenter, Kenneth G.; Petrone, Peter;
   Dogoda, Peter; Reed, Daniel; Mozurkewich, David
Bibcode: 2008SPIE.7011E..31L
Altcode: 2008SPIE.7011E..89L
  Stellar Imager (SI) is a proposed NASA space-based UV imaging
  interferometer to resolve the stellar disks of nearby stars. SI would
  consist of 20 - 30 separate spacecraft flying in formation at the
  Earth-Sun L2 libration point. Onboard wavefront sensing and control
  is required to maintain alignment during science observations and
  after array reconfigurations. The Fizeau Interferometry Testbed (FIT),
  developed at the NASA/Goddard Space Flight Center, is being used to
  study wavefront sensing and control methodologies for Stellar Imager
  and other large, sparse aperture telescope systems. FIT initially
  consists of 7 articulated spherical mirrors in a Golay pattern, and
  is currently undergoing expansion to 18 elements. FIT currently uses
  in-focus whitelight sparse aperture PSFs and a direct solve broadband
  phase retrieval algorithm to sense and control its wavefront. Ultimately
  it will use extended scene wavelength, with a sequential diversity
  algorithm that modulates a subset of aperture pistons to jointly
  estimate the wavefront and the reconstructed image from extended
  scenes. The recovered wavefront is decomposed into the eigenmodes of
  the control matrix and actuators are moved to minimize the wavefront
  piston, tip and tilt in closed-loop. We discuss the testbed, wavefront
  control methodology and ongoing work to increase its bandwidth from
  1 per 11 seconds to a few 10's of Hertz and show ongoing results.

Title: Atmospheric Dynamics in α Tau
Authors: Airapetian, Vladimir; Carpenter, K. G.
Bibcode: 2008AAS...21116215A
Altcode:
  HST/GHRS, HST/STIS and FUSE observations of evolved late-type stars
  demonstrated the presence of non-thermally broadened UV emission
  lines forming at temperatures of 10,000 to 300,000K in almost all
  of the stars. In this study we analyze CI 1993.62A, CII] 2323.5A,
  SiIII 2350.17A, SiIV 1393A, CIII 977A, OIV 1401.35A and OVI 1032A
  emission lines from Tau. Our analysis of these UV lines reveal
  redshifts T (except for OVI 1032A), while non-thermal velocities T
  . Derived emission measures indicate filling factors &lt;0.1%. These
  findings force us to reconsider the definition of chromospheric and
  transition regions in these stars as patchy regions or atmospheric
  hot spots. According to Freytag et al. (2002), convective cells with
  sizes of 0.01R<SUB>star</SUB> generate shock waves that dissipate
  at lower atmospheric layers. Large-scale convective motions produce
  large-scale magnetic structures in contrast to arcades of thin
  solar-like loops powered by small-scale granular motions. We discuss
  the model of non-linear Alfven waves amplified by resonant interaction
  with sound waves and propagating upward along one (or a few) constant
  pressure large-scale loop(s). As Alfven waves propagate upward in a
  gravitationally stratified atmosphere, their wave amplitudes increase
  causing non-thermal broadening in UV lines due to unresolved wave
  motions. We discuss a model that predicts downward plasma motions
  in extended loops driven by asymmetric Alfven wave heating. We
  use a state-of-the-art 2.5 MHD code to show that the energy flux
  density of Alfven waves (with P a few days), which are needed to
  explain the radiative cooling and non-thermal broadening in the
  UV lines, is consistent with the requirement to drive massive ( 10
  M<SUB>Sun</SUB>/yr) and slow ( 30 km/s) stellar winds from magnetically
  open structures with the assumption of a magnetic field at the wind
  base 1 G. <P />This research is supported by the NASA Research grant
  to CUA from GSFC No. NASA-NNG06GJ29G

Title: The Stellar Imager
Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska,
   Margarita
Bibcode: 2008nssv.book..191C
Altcode:
  No abstract at ADS

Title: Towards a Small Prototype Planet Finding Interferometer:
    The next step in planet finding and characterization in the infrared
Authors: Danchi, W. C.; Deming, D.; Carpenter, K. G.; Barry, R. K.;
   Hinz, P.; Johnston, K. J.; Lawson, P.; Lay, O.; Monnier, J. D.;
   Richardson, L. J.; Rinehart, S.; Traub, W.
Bibcode: 2008arXiv0801.4752D
Altcode:
  During the last few years, considerable effort has been directed
  towards large-scale (&gt;&gt; $1 Billion US) missions to detect
  and characterize earth-like planets around nearby stars, such as
  the Terrestrial Planet Finder Interferometer (TPF-I) and Darwin
  missions. However, technological and budgetary issues as well as
  shifting science priorities will likely prevent these missions from
  entering Phase A until the next decade. The secondary eclipse technique
  using the Spitzer Space Telescope has been used to directly measure
  the temperature and emission spectrum of extrasolar planets. However,
  only a small fraction of known extrasolar planets are in transiting
  orbits. Thus, a simplified nulling interferometer, which produces
  an artificial eclipse or occultation, and operates in the near-
  to mid-infrared (e.g. ~ 3 to 8 or 10 microns), can characterize the
  atmospheres of this much larger sample of the known but non-transiting
  exoplanets. Many other scientific problems can be addressed with a
  system like this, including imaging debris disks, active galactic
  nuclei, and low mass companions around nearby stars. We discuss the
  rationale for a probe-scale mission in the $600-800 Million range,
  which we name here as the Small Prototype Planet Finding Interferometer
  (SPPFI).

Title: Wavefront sensing and closed-loop control for the Fizeau
    interferometry testbed
Authors: Lyon, Richard G.; Carpenter, Kenneth G.; Liu, Alice; Petrone,
   Peter; Dogoda, Peter; Reed, Daniel; Mozurkewich, David
Bibcode: 2007SPIE.6687E..0HL
Altcode:
  Stellar Imager (SI) is a proposed NASA space-based UV imaging
  interferometer to resolve the stellar disks of nearby stars. SI would
  consist of 20 - 30 separate spacecraft flying in formation at the
  Earth-Sun L2 libration point. Onboard wavefront sensing and control
  is required to maintain alignment during science observations and
  after array reconfigurations. The Fizeau Interferometry Testbed (FIT),
  developed at the NASA/Goddard Space Flight Center, is being used to
  study wavefront sensing and control methodologies for Stellar Imager
  and other large, sparse aperture telescope systems. FIT initially
  consists of 7 articulated spherical mirrors in a Golay pattern, and
  is currently undergoing expansion to 18 elements. FIT currently uses
  in-focus whitelight sparse aperture PSFs and a direct solve phase
  retrieval algorithm to sense and control its wavefront. Ultimately
  it will use extended scene wavelength, with a sequential diversity
  algorithm that modulates a subset of aperture pistons to jointly
  estimate the wavefront and the reconstructed image from extended
  scenes. The recovered wavefront is decomposed into the eigenmodes of
  the control matrix and actuators are moved to minimize the wavefront
  piston, tip and tilt in closed-loop. We discuss the testbed, wavefront
  control methodology and ongoing work to increase its bandwidth from
  1 per 11 seconds to a few 10's of Hertz and show ongoing results.

Title: Beam combination for Stellar Imager and its application to
    full-aperture imaging
Authors: Mozurkewich, D.; Carpenter, K. G.; Lyon, R. G.
Bibcode: 2007SPIE.6687E..0KM
Altcode: 2007SPIE.6687E..19M
  Stellar Imager (SI) will be a Space-Based telescope consisting of 20
  to 30 separated apertures. It is designed for UV/Optical imaging of
  stellar surfaces and asteroseismology. This report describes details
  of an alternative optical design for the beam combiner, dubbed the
  Spatial Frequency Remapper (SFR). It sacrifices the large field of view
  of the Fizeau combiner. In return, spectral resolution is obtained
  with a diffraction grating rather than an array of energy-resolving
  detectors. The SFR design works in principle and has been implemented
  with MIRC at CHARA for a small number of apertures. Here, we show
  the number of optical surfaces can be reduced and the concept
  scales gracefully to the large number of apertures needed for
  Stellar Imager. We also describe a potential application of this
  spatial frequency remapping to improved imaging with filled-aperture
  systems. For filled-aperture imaging, the SFR becomes the core of an
  improved aperture masking system. To date, aperture-masking has produced
  the best images with ground-based telescopes but at the expense of
  low sensitivity due to short exposures and the discarding of most
  of the light collected by the telescope. This design eliminates
  the light-loss problem previously claimed to be inherent in all
  aperture-masking designs. We also argue that at least in principle,
  the short-integration time limit can also be overcome. With these
  improvements, it becomes an ideal camera for TPF-C; since it can form
  speckle-free images in the presence of wavefront errors, it should
  significantly relax the stability requirements of the current designs.

Title: Direct UV/optical imaging of stellar surfaces: the Stellar
    Imager Vision Mission
Authors: Carpenter, Kenneth G.; Lyon, Richard G.; Schrijver, Carolus;
   Karovska, Margarita; Mozurkewich, David
Bibcode: 2007SPIE.6687E..0GC
Altcode: 2007SPIE.6687E..15C
  The Stellar Imager (SI) is a UV/optical, space-based interferometer
  designed to enable 0.1 milli-arcsecond (mas) spectral imaging of
  stellar surfaces and, via asteroseismology, stellar interiors and of
  the Universe in general. SI's science focuses on the role of magnetism
  in the Universe, particularly on magnetic activity on the surfaces of
  stars like the Sun. SI's prime goal is to enable long-term forecasting
  of solar activity and the space weather that it drives, in support of
  the Living with a Star program in the Exploration Era. SI will also
  revolutionize our understanding of the formation of planetary systems,
  of the habitability and climatology of distant planets, and of many
  magneto-hydrodynamically controlled processes in the Universe. SI
  is a "Flagship and Landmark Discovery Mission" in the 2005 Sun Solar
  System Connection (SSSC) Roadmap and a candidate for a "Pathways to
  Life Observatory" in the Exploration of the Universe Division (EUD)
  Roadmap (May, 2005). We discuss herein the science goals of the SI
  Mission, a mission architecture that could meet those goals, and the
  technologies needed to enable this mission. Additional information on
  SI can be found at: http://hires.gsfc.nasa.gov/si/.

Title: Dynamos, Asteroseismology, and the Stellar Imager
Authors: Schrijver, C. J.; Carpenter, K. G.; Karovska, M.
Bibcode: 2007CoAst.150..364S
Altcode:
  The ultra-sharp images of the Stellar Imager (SI) will revolutionize
  our view of many dynamic astrophysical processes: The 0.1 milli-arcsec
  resolution of this deep-space telescope will transform point sources
  into extended sources, and simple snapshots into spellbinding evolving
  views. SI's science focuses on the role of magnetism in the Universe,
  particularly on magnetic activity on the surfaces of stars like the Sun
  and on the subsurface flows that drive this activity. SI's prime goal
  is to image magnetically active stars with enough resolution to map
  their evolving dynamo patterns and their internal flows. By exploring
  the Universe at ultra-high resolution, SI will also revolutionize our
  understanding of the formation of planetary systems, of the habitability
  and climatology of Earth as well as distant exoplanets, and of many
  magneto-hydrodynamically controlled structures and processes in the
  Universe. <P />See http://hires.gsfc.nasa.gov/si/ for details on the
  Stellar Imager mission.

Title: Stellar Imager
Authors: Carpenter, Kenneth
Bibcode: 2007STIN...0734890C
Altcode:
  The Stellar Imager (SI) is one of NASA's "Vision Missions" - concepts
  for future, space-based, strategic missions that could enormously
  increase our capabilities for observing the Cosmos. SI is designed
  as a UV/Optical Interferometer which will enable 0.1 milli-arcsecond
  (mas) spectral imaging of stellar surfaces and, via asteroseismology,
  stellar interiors and of the Universe in general. The ultra-sharp images
  of the Stellar Imager will revolutionize our view of many dynamic
  astrophysical processes by transforming point sources into extended
  sources, and snapshots into evolving views. SI, with a characteristic
  angular resolution of 0.1 milli-arcseconds at 2000 Angstroms, represents
  an advance in image detail of several hundred times over that provided
  by the Hubble Space Telescope. The Stellar Imager will zoom in on what
  today-with few exceptions - we only know as point sources, revealing
  processes never before seen, thus providing a tool as fundamental to
  astrophysics as the microscope is to the study of life on Earth. SI's
  science focuses on the role of magnetism in the Universe, particularly
  on magnetic activity on the surfaces of stars like the Sun. It's prime
  goal is to enable long-term forecasting of solar activity and the space
  weather that it drives, in support of the Living With a Star program
  in the Exploration Era. SI will also revolutionize our understanding of
  the formation of planetary systems, of the habitability and climatology
  of distant planets, and of many magneto-hydrodynamically controlled
  processes in the Universe. Stellar Imager is included as a "Flagship
  and Landmark Discovery Mission" in the 2005 Sun Solar System Connection
  (SSSC) Roadmap and as a candidate for a "Pathways to Life Observatory"
  in the Exploration of the Universe Division (EUD) Roadmap (May, 2005)
  and as such is a candidate mission for the 2025-2030 timeframe. An
  artist's drawing of the current "baseline" concept for SI is presented.

Title: Steps Toward a UV/Optical Interferometer in Space: FIT &amp;
    SIFFT
Authors: Carpenter, Kenneth G.; Lyon, R. G.; Liu, A.; Dogoda, P.;
   Petrone, P.; Mozurkewich, D.; Miller, D.; Mohan, S.; Stahl, P.
Bibcode: 2006AAS...20916401C
Altcode: 2006BAAS...38R1129C
  We summarize the goals and result-to-date of a ROSES/APRA-sponsored
  program to develop two of the major technologies needed to enable
  the design and construction of future large baseline, space-based
  Interferometric and Sparse Aperture Telescope missions (e.g., Stellar
  Imager, Life Finder, Black Hole Imager, and Planet Imager). The Fizeau
  Interferometer Testbed (FIT) is being used to develop and demonstrate
  nm-level, closed-loop optical control of mirrors (i.e., control of tip,
  tilt, piston, translation of array elements) and the overall system
  to keep multiple beams in phase and optimize imaging of a Fizeau
  interferometric system and to assess various image reconstruction
  algorithms (phase diversity, clean, maximum entropy method, etc.) for
  utility and accuracy. The Synthetic Imaging Formation Flying Testbed
  (SIFFT) is, in parallel, being used to develop and demonstrate
  algorithms for autonomous cm-level precision formation flying, which
  can be combined in the future with the higher precision optical control
  systems (e.g., those developed on the FIT) to fully enable synthetic
  aperture imaging systems. The ultimate goal of this research is the
  demonstration of closed-loop performance of a unified system which
  combines formation flying and nm-level optical control systems (based
  on analysis of the science data stream) to maintain phasing of a large
  array of space-borne mirrors, as needed for missions like those listed
  above, as well as smaller baseline Precursor missions that may pave
  the path to the larger strategic missions.

Title: Heavy Element Abundances in the Photospheres of Cool
    Supergiants
Authors: Wahlgren, Glenn M.; Lundqvist, M.; Carpenter, K. G.
Bibcode: 2006AAS...209.9304W
Altcode: 2006BAAS...38.1030W
  We report on a program to determine the chemical composition of massive,
  cool supergiant photospheres. We concentrate on elements heavier than
  the iron group, addressing the question of whether nuclear by-products
  from the weak s-process have been brought to the surface by convective
  processes. For massive stars, atoms with mass up to approximately
  A = 100 are thought to be formed by neutron capture via the weak
  s-process. The abundances of these elements have been calculated
  by other researchers to be a function of stellar mass. <P />Our
  initial work has concentrated on the identification of useful atomic
  spectral lines at infrared wavelengths, where absorption from molecular
  species is reduced relative to that at optical wavelengths for M-type
  stars. Abundances are determined by synthetic spectrum fitting to line
  profiles in high-resolution spectra. <P />We present results for the
  cool, supergiant Betelgeuse (M2 Iab). Abundances are determined for a
  number of heavy elements, and despite large uncertainties attributed to
  the available atomic data (oscillator strengths), a distinct enhancement
  of Sr is determined after correcting for non-LTE effects. Such an
  enhancement is predicted by models of interior nucleosynthesis via
  neutron capture. Our results illuminate the problems that must be
  overcome before being able to derive abundances with the accuracy
  required for rigorous comparison with theoretical calculations. We
  also present our approach to applying the results for Betelgeuse to
  additional cool supergiants.

Title: The Stellar Imager (SI) vision mission
Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska,
   Margarita
Bibcode: 2006SPIE.6268E..21C
Altcode: 2006astro.ph..6411C; 2006SPIE.6268E..63C
  The Stellar Imager (SI) is a UV-Optical, Space-Based Interferometer
  designed to enable 0.1 milli-arcsecond (mas) spectral imaging of
  stellar surfaces and of the Universe in general and asteroseismic
  imaging of stellar interiors. SI is identified as a "Flagship and
  Landmark Discovery Mission" in the 2005 Sun Solar System Connection
  (SSSC) Roadmap and as a candidate for a "Pathways to Life Observatory"
  in the Exploration of the Universe Division (EUD) Roadmap (May,
  2005). SI will revolutionize our view of many dynamic astrophysical
  processes: its resolution will transform point sources into extended
  sources, and snapshots into evolving views. SI's science focuses
  on the role of magnetism in the Universe, particularly on magnetic
  activity on the surfaces of stars like the Sun. SI's prime goal is to
  enable long-term forecasting of solar activity and the space weather
  that it drives. SI will also revolutionize our understanding of the
  formation of planetary systems, of the habitability and climatology
  of distant planets, and of many magneto-hydrodynamically controlled
  processes in the Universe. The results of the SI "Vision Mission"
  Study are presented in this paper. Additional information on the SI
  mission concept and related technology development can be found at URL:
  http://hires.gsfc.nasa.gov/si/.

Title: SI - The Stellar Imager: Results from the Vision Mission Study
Authors: Carpenter, K. G.; Schrijver, C. J.; Karovska, M.; SI Vision
   Mission Study Team
Bibcode: 2005AAS...207.2307C
Altcode: 2005BAAS...37R1196C
  The Stellar Imager (SI) is a UV-Optical, Space-Based Interferometer
  designed to enable 0.1 milli-arcsecond (mas) spectral imaging of
  stellar surfaces and stellar interiors (via asteroseismology) and of
  the Universe in general. SI was included as a "far horizon" or "Vision
  Mission" in the 2000 and 2003 SEC Roadmaps and is now identified as
  a "Flagship and Landmark Discovery Mission" in the 2005 Sun Solar
  System Connection (SSSC) Roadmap and as a candidate for a "Pathways
  to Life Observatory" in the Exploration of the Universe Division (EUD)
  Roadmap (May, 2005). The ultra-sharp images of the Stellar Imager will
  revolutionize our view of many dynamic astrophysical processes: The
  0.1 mas resolution of this deep-space telescope will transform point
  sources into extended sources, and snapshots into evolving views. SI's
  science focuses on the role of magnetism in the Universe, particularly
  on magnetic activity on the surfaces of stars like the Sun. SI's prime
  goal is to enable long-term forecasting of solar activity and the space
  weather that it drives in support of the Living With a Star program in
  the Exploration Era. SI will also revolutionize our understanding of
  the formation of planetary systems, of the habitability and climatology
  of distant planets, and of many magneto-hydrodynamically controlled
  processes in the Universe. The results of a just-concluded "Vision
  Mission" Study of Stellar Imager will be presented in this paper. <P
  />This work was supported, in part, by Vision Mission Study grants
  from NASA HQ to NASA-GSFC and from GSFC to Smithsonian Astrophysical
  Observatory, Seabrook Engineering, SUNY/Stonybrook, U. Colorado/Boulder,
  and STScI. Substantial complementary internal institutional support
  is gratefully acknowledged from all of the participating institutions.

Title: High-Mass Triple Systems: The Classical Cepheid Y Carinae
Authors: Evans, Nancy Remage; Carpenter, Kenneth G.; Robinson, Richard;
   Kienzle, Francesco; Dekas, Anne E.
Bibcode: 2005AJ....130..789E
Altcode: 2005astro.ph..4169E
  We have obtained a Hubble Space Telescope STIS ultraviolet
  high-dispersion echelle-mode spectrum of the binary companion of the
  double-mode classical Cepheid Y Car. The velocity measured for the
  hot companion from this spectrum is very different from reasonable
  predictions for binary motion, implying that the companion is
  itself a short-period binary. The measured velocity changed by
  7 km s<SUP>-1</SUP> during the 4 days between two segments of the
  observation, confirming this interpretation. We summarize ``binary''
  Cepheids that are in fact members of a triple system and find that
  at least 44% are triples. The summary of information on Cepheids
  with orbits makes it likely that the fraction is underestimated. <P
  />Based on observations made with the NASA/ESA Hubble Space Telescope,
  obtained at the Space Telescope Science Institute, which is operated
  by the Association of Universities for Research in Astronomy, Inc.

Title: The Stellar Imager: a deep-space telescope to image stellar
    surfaces
Authors: Schrijver, C. J.; Carpenter, K. G.; Karovska, M.; Si Vision
   Mission Team
Bibcode: 2005ESASP.560..951S
Altcode: 2005csss...13..951S
  No abstract at ADS

Title: Planetary Environment Study at Sub-milliarcsecond Resolution
Authors: Ragozzine, D.; Karovska, M.; Hartmann, L.; Sasselov, D.;
   Carpenter, K.; SI Team
Bibcode: 2004AAS...205.1718R
Altcode: 2004BAAS...36.1368R
  The Stellar Imager (SI; http://hires.gsfc.nasa.gov/ ∼si ) is
  a NASA Vision Mission, conceived of as a space-based UV-Optical
  long-baseline interferometer that will provide sub-milliarcsecond
  imaging capabilities. We present results from our study of how
  SI could be used to answer key questions about planet formation
  and planet-star-disk interactions. SI would be able to resolve
  and characterize star-disk interactions at a few stellar radii,
  including accretion and inner disk edge heating. Simple models of
  T-Tauri stars are used to probe SI's sensitivity to various critical
  parameters and geometries. By observing H2-flourescent lines in the
  UV, the contrast between the luminosity of the star and the gas can
  be improved. A list of potential targets among known planet-harboring
  stars is also presented with the hope of resolving possible star-planet
  interactions. <P />Acknowledgement: This work was supported by the SI
  Vision Mission study grant NNG04GM92G from NASA/GSFC to SAO. MK is a
  member of the Chandra X-ray Center (NASA contract NAS8-39073).

Title: Stellar Imager (SI) Vision Mission Science Drivers
Authors: Karovska, M.; Carpenter, K. G.; Schrijver, C. J.; SI Mission
   Concept Development
Bibcode: 2004AAS...20518005K
Altcode: 2005BAAS...37..384K
  We describe the key scientific drivers for the Stellar Imager (SI)
  Vision Mission - a UV-optical 0.1 milli-arcsecond (mas) imaging space
  interferometer. Ultra-high sub-mas angular resolution imaging at UV and
  optical wavelengths is key to studies of magnetic field structures that
  govern the formation of stars and planetary systems, the habitability of
  planets, long-term space weather in the Exploration era, and transport
  processes on many scales in the Universe. Magnetic fields affect the
  evolution of structure in the Universe and drive solar and stellar
  activity which is a key to life's origin and survival. However,
  our understanding of how magnetic fields form, operate, and evolve
  is currently very limited, even for the nearest star, our Sun. <P
  />The key science goal of the Stellar Imager Mission is to obtain an
  understanding of stellar dynamos, and in particular the solar dynamo,
  through a population study of other stars representing a broad range
  of stellar parameters and activity. The end goal is to understand the
  variable impact of stellar magnetic activity on planetary climates and
  the origin and maintenance of life. Improved knowledge of solar-type
  dynamo activity and the interaction of global fields and flows
  is also crucial for developing models for long-term space weather
  forcasting. Furthermore, SI's high-angular resolution capabilities, over
  two magnitudes better then the HST, will enable unprecedented studies
  of dynamo and accretion-driven processes, and mass exchange and mass
  flows in a wide variety of galactic and extragalactic sources, including
  young star/disk systems, solar-type and evolved stars and astrospheres,
  numerous interacting binaries, and SN, AGN, and black hole environments.

Title: The Stellar Imager (SI): Preliminary Results from the Ongoing
    Vision Mission Study
Authors: Carpenter, K. G.; Schrijver, C. J.; SI Mission Concept
   Development Team
Bibcode: 2004AAS...205.0509C
Altcode: 2004BAAS...36.1342C; 2004AAS...205..509C
  The Stellar Imager (SI) is a "Vision Mission" in the far-horizon
  NASA Roadmap, conceived for the purpose of understanding the
  effects of stellar magnetic fields, the dynamos that generate them,
  and the internal structure and dynamics of the stars in which they
  exist. The ultimate goal is to achieve the best possible forecasting
  of solar/stellar activity and to understand the impact of that
  activity on planetary climates and the origin and maintenance of
  life in the Universe. The science goals of SI require an ultra-high
  angular resolution, at ultraviolet wavelengths, on the order of 100
  micro-arcsec and baselines on the order of 0.5 km. SI's resolution will
  make it an invaluable resource for many other areas of astrophysics,
  including studies of AGN's, supernovae, cataclysmic variables, young
  stellar objects, QSO's, and stellar black holes. These requirements
  call for a large, multi-spacecraft (&gt;20) imaging interferometer,
  utilizing precision formation flying in a stable environment, such as
  in a Lissajous orbit around the Sun-Earth L2 point. In this paper,
  we present an update on the ongoing SI Vision Mission concept and
  technology development studies. <P />The SI Mission Concept Study is
  supported, in part, by grants from NASA-HQ through the 2003 Vision
  Mission NRA.

Title: Apodized square aperture plus occulter concept for TPF
Authors: Jordan, Ian J. E.; Schultz, Alfred B.; Lyon, Richard G.; Hart,
   Helen M.; Bruhweiler, Frederick; Fraquelli, Dorothy A.; Carpenter,
   Kenneth G.; Kochte, Mark; Hollis, Jan M.
Bibcode: 2004SPIE.5487.1391J
Altcode:
  The standard approach to achieving TPF-level starlight suppression
  has been to couple a few techniques together. Deployment of a low-
  or medium-performance external occulter as the first stage of
  starlight suppression reduces manufacturing challenges, mitigates
  under-performance risks, lowers development costs, and hastens
  launch date for TPF. This paper describes the important aspects of a
  conceptual 4-metre apodized square aperture telescope system utilizing a
  low-performance external occulter. Adding an external occulter to such a
  standard TPF design provides a benefit that no other technique offers:
  scattered and diffracted on-axis starlight is suppressed by orders of
  magnitude before reaching the telescope. This translates directly into
  relaxed requirements on the remainder of the optical system.

Title: Metrology and pointing for astronomical interferometers
Authors: Phillips, James D.; Carpenter, Kenneth G.; Gendreau, Keith
   C.; Karovska, Margarita; Kaaret, Philip E.; Reasenberg, Robert D.
Bibcode: 2004SPIE.5491..320P
Altcode:
  Metrology and pointing will be enabling technologies for a new
  generation of astronomical missions having large and distributed
  apertures and delivering unprecedented performance. The UV
  interferometer Stellar Imager would study stellar dynamos by imaging
  magnetic activity on the disks of stars in our Galaxy. The X-ray
  interferometer Black Hole Imager would study strong gravity physics and
  the formation of jets by imaging the event horizons of supermassive
  black holes. These missions require pointing to microarcseconds or
  better, and metrology to nm accuracy of optical elements separated by
  km, for control of optical path difference. This paper describes a
  metrology and pointing system that meets these requirements for the
  Stellar Imager. A reference platform uses interferometers to sense
  alignment with a guide star. Laser gauges determine mirror positions in
  the frame of the reference platform, and detector position is monitored
  by laser gauges or observations of an artificial star. Applications
  to other astronomical instruments are discussed.

Title: The Fizeau interferometer testbed (FIT): developing and
    testing the technologies needed for space-based interferometric
    imaging systems
Authors: Mazzuca, Lisa M.; Carpenter, Kenneth G.; Lyon, Richard G.;
   Marzouk, Joe; Petrone, Peter, III; Cottle, Paul; Dogoda, Peter; Huet,
   Hubert; Liiva, Peter; Mozurkewich, David; Armstrong, J. T.; Zhang,
   Xiaolei; Solyar, Gregory; Mundy, Lee G.
Bibcode: 2004SPIE.5491.1034M
Altcode:
  The Fizeau Interferometer Testbed (FIT) is a ground-based laboratory
  experiment at Goddard Space Flight Center (GSFC) designed to develop
  and test technologies that will be needed for future interferometric
  spacecraft missions. Specifically, the research from this experiment
  is a proof-of-concept for optical accuracy and stability, closed-loop
  control algorithms, optimal sampling methodology of the Fourier
  UV-plane, computational models for system performance, and image
  synthesis techniques for a sparse array of 7 to 30 mirrors. It will
  assess and refine the technical requirements on hardware, control,
  and imaging algorithms for the Stellar Imager (SI), its pathfinder
  mission, and other sparse aperture and interferometric imaging mission
  concepts. This ground-based optical system is a collaborative effort
  between NASA's GSFC, Sigma Space Corporation, the Naval Research
  Laboratory, and the University of Maryland. We present an overview of
  the FIT design goals and explain their associated validation methods. We
  further document the design requirements and provide a status on their
  completion. Next, we show the overall FIT design, including the optics
  and data acquisition process. We discuss the technologies needed
  to insure success of the testbed as well as for an entire class of
  future mission concepts. Finally, we compare the expected performance
  to the actual performance of the testbed using the initial array of
  seven spherical mirrors. Currently, we have aligned and phased all
  seven mirrors, demonstrated excellent system stability for extended
  periods of time, and begun open-loop operations using "pinhole" light
  sources. Extended scenes and calibration masks are being fabricated
  and will shortly be installed in the source module. Installation of
  all the different phase retrieval/diversity algorithms and control
  software is well on the way to completion, in preparation for future
  tests of closed-loop operations.

Title: Fizeau interferometry testbed: wavefront control
Authors: Lyon, Richard G.; Carpenter, Kenneth G.; Mazzuca, Lisa;
   Huet, Hubert; Cottle, Paul W.; Petrone, Peter P., III; Dagoda, Peter;
   Liiva, Peter; Marzouk, Joe; Solyar, Gregory; Mozurkewich, David;
   Zhang, Xiaolei; Armstrong, Thomas
Bibcode: 2004SPIE.5487..963L
Altcode:
  Stellar Imager (SI) is a potential NASA space-based UV imaging
  interferometer to resolve the stellar disks of nearby stars. SI
  would consist of 20 - 30 separate spacecraft flying in formation at
  the Earth-Sun L2 libration point. Onboard wavefront control would
  be required to initially align the formation and maintain alignment
  during science observations and after array reconfiguration. The Fizeau
  Interferometry Testbed (FIT) is a testbed currently under development
  at the NASA/Goddard Space Flight Center to develop and study the
  wavefront control methodologies for Stellar Imager and other large,
  sparse aperture telescope systems. FIT consists of 7 articulated
  spherical mirrors in a Golay pattern, expandable up to 30 elements,
  and reconfigurable into multiple array patterns. FIT"s purpose is to
  demonstrate image quality versus array configuration and to develop
  and advance the wavefront control for SI. FIT uses extended scene
  wavelength, focus and field diversity to estimate the wavefront across
  the set of apertures. The recovered wavefront is decomposed into the
  eigenmodes of the control matrix and actuators are moved to minimize the
  wavefront piston, tip and tilt. Each mirror"s actuators are 3 degrees of
  freedom, however, they do not move each of the mirrors about a point on
  each mirrors surface, thus the mapping from wavefront piston, tip/tilt
  to mirror piston, tip/tilt is not diagonal. We initially estimate this
  mapping but update it as part of wavefront sensing and control process
  using system identification techniques. We discuss the FIT testbed,
  wavefront control methodology, and show initial results from FIT.

Title: Fabrication and characterization of the Fizeau interferometer
    testbed
Authors: Petrone, Peter, III; Carpenter, Kenneth G.; Clark, Dave;
   Cottle, Paul; Dogoda, Peter; Huet, Hubert; Liiva, Peter; Lyon, Richard
   G.; Marzouk, Joe; Mazzuca, Lisa M.; McAndrew, Dave; Solyar, Gregory
Bibcode: 2004SPIE.5491.1776P
Altcode:
  The Fizeau Interferometer Testbed (FIT) is a ground-based system that
  will be used for the development and testing of technologies relevant
  to Stellar Imager (SI) and other sparse aperture/Fizeau imaging
  interferometer mission concepts. The testbed will utilize image-based
  wavefront sensing and control to co-phase and maintain closed-loop
  control over a Sparse Aperture Array (SAA) consisting of spherical
  mirror elements. The SAA is a re-configurable assembly baselined to
  incorporate between seven (initially) and thirty 12.5mm diameter (R =
  4000mm) mirror elements. In this paper we describe the fabrication,
  alignment, and initial calibration of the phase I (7 primary elements)
  FIT hardware and discuss various factors impacting the performance
  and stability of the testbed.

Title: The Stellar Imager (SI): a revolutionary large-baseline
    imaging interferometer at the Sun-Earth L2 point
Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Allen, Ronald
   J.; Brown, Alexander; Chenette, David; Danchi, William C.; Karovska,
   Margarita; Kilston, Steven; Lyon, Richard G.; Marzouk, Joe; Mazzuca,
   Lisa M.; Moe, Rud V.; Walter, Frederick; Murphy, Neil
Bibcode: 2004SPIE.5491..243C
Altcode:
  The Stellar Imager (SI) is a far-horizon or "Vision" mission in the
  NASA Sun-Earth Connection (SEC) Roadmap, conceived for the purpose
  of understanding the effects of stellar magnetic fields, the dynamos
  that generate them, and the internal structure and dynamics of the
  stars in which they exist. The ultimate goal is to achieve the best
  possible forecasting of solar/stellar activity and its impact on life
  in the Universe. The science goals of SI require an ultra-high angular
  resolution, at ultraviolet wavelengths, on the order of 0.1 milliarcsec
  and thus baselines on the order of 500 meters. These requirements
  call for a large, multi-spacecraft (&gt;20) imaging interferometer,
  utilizing precision formation flying in a stable environment, such as
  in a Lissajous orbit around the Sun-Earth L2 point. SI's resolution
  (several 100 times that of HST) will make it an invaluable resource
  for many other areas of astrophysics, including studies of AGN's,
  supernovae, cataclysmic variables, young stellar objects, QSO's,
  and stellar black holes. In this paper, we present an update on
  the ongoing mission concept and technology development studies for
  SI. These studies are designed to refine the mission requirements
  for the science goals, define a Design Reference Mission, perform
  trade studies of selected major technical and architectural issues,
  improve the existing technology roadmap, and explore the details of
  deployment and operations, as well as the possible roles of astronauts
  and/or robots in construction and servicing of the facility.

Title: Imaging Terrestrial Planets
Authors: Kochte, M.; Schultz, A. B.; Fraquelli, D.; Jordan, I. J. E.;
   Lyon, R. G.; Carpenter, K. G.; Hart, H. M.; Disanti, M.; Bruhweiler,
   F.; Miskey, C.; Rodrigue, M.; Fadali, M. S.; Skelton, D.; Cheng, K. -P.
Bibcode: 2004AIPC..713..223K
Altcode:
  We present optical simulations of a new approach to directly image
  terrestrial planets. Terrestrial planets typically are 10 orders
  of magnitude fainter than the central star, a difficult challenge
  for any optical system. Our studies show that the combination
  of an external occulter and an apodizer yields the required
  contrast, with significantly reduced requirements on stray light and
  diffraction. This mitigates the very high mirror tolerances required
  of other coronagraphic methods and makes exo-planet detection feasible
  with current technology.

Title: The Fizeau Interferometer Testbed (FIT): Developing and
    Testing the Technologies Needed for Space-Based Interferometric
    Imaging Systems
Authors: Mazzuca, L. M.; Carpenter, K. G.; Lyon, R. G.; Marzouk, J.;
   Cottle, P.; Dogoda, P.; Huet, H.; Liiva, P.; Petrone, P.; Armstrong,
   J. T.; Zhang, X.; Mundy, L.; Mozurkewich, D.; Solyar, G.
Bibcode: 2004AAS...204.0812M
Altcode: 2004BAAS...36..791M
  The Fizeau Interferometer Testbed (FIT) is a ground-based laboratory
  experiment at Goddard Space Flight Center (GSFC) designed to develop
  and test technologies that will be needed for future interferometric
  spacecraft missions. Specifically, the research from this experiment
  is a proof-of-concept for optical accuracy and stability, closed-loop
  control algorithms, optimal sampling methodology of the Fourier
  UV-plane, computational models for system performance, and image
  synthesis techniques for a sparse array of 7 to 30 mirrors. It will
  assess and refine the technical requirements on hardware, control,
  and imaging algorithms for the Stellar Imager (SI), its pathfinder
  mission, and other sparse aperture and interferometric imaging mission
  concepts. This ground-based optical system is a collaborative effort
  between NASA's GSFC, Sigma Space Corporation, the Naval Research
  Laboratory, and the University of Maryland. We present an overview
  of the final optical design, detector system, and data acquisition
  process. We further compare the expected performance to the actual
  performance of the testbed using the initial array of seven spherical
  mirrors. Currently, we have aligned and phased all seven mirrors,
  demonstrated excellent system stability for extended periods of time,
  and begun open-loop operations using "pinhole" light sources. Extended
  scenes and calibration masks are being fabricated and will shortly
  be installed in the source module. Installation of all the different
  phase retrieval/diversity algorithms and control software is well on
  the way to completion, in preparation for future tests of closed-loop
  operations.

Title: The O VI and C III Lines at 1032 and 977 Å in Hyades F Stars
Authors: Böhm-Vitense, Erika; Robinson, Richard D.; Carpenter,
   Kenneth G.
Bibcode: 2004ApJ...606.1174B
Altcode:
  We continue our investigations into the mechanisms heating the outer
  layers of cool dwarf stars. In this study we specifically seek to
  determine whether in the layers with temperatures around 250,000-300,000
  K, in which the O VI lines are emitted, the temperatures are determined
  by heat conduction from the coronae or by the same processes that
  heat the lower temperature regions. To study this we discuss here 22
  spectra of Hyades F stars taken by the Far Ultraviolet Spectroscopic
  Explorer (FUSE) satellite to study the O VI lines at 1032 Å and the C
  III lines at 977 Å and compare them with other lower transition layer
  lines, observed with HST and IUE, and with existing X-ray data. For our
  targets with B-V&gt;0.4, the X-ray fluxes of single F stars increase,
  on average, slowly with increasing B-V, while the O VI line fluxes show
  the same steep decrease around B-V=0.43 as previously found for the
  lower temperature transition layer lines. For single stars the X-ray
  fluxes decrease with increasing vsini, except for the stars with B-V
  between 0.418 and 0.455, while for the O VI lines, as for the other
  transition layer lines, fluxes increase with increasing vsini, if vsini
  is larger than 30 km s<SUP>-1</SUP>. For smaller vsini, line fluxes are
  independent of vsini. The B-V and vsini dependences of the O VI line
  fluxes are then very different from those of the X-ray fluxes. We thus
  conclude that for electron temperature T<SUB>e</SUB> below 300,000 K,
  the transition layers for Hyades F stars are not mainly heated by
  heat conduction from their coronae. <P />Based on observations made
  with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer (FUSE)
  telescope, which is operated for NASA by Johns Hopkins University,
  under contract NAS5-32985.

Title: The Stellar Imager (SI) ``Vision Mission"
Authors: Carpenter, K.; Danchi, W.; Leitner, J.; Liu, A.; Lyon,
   R.; Mazzuca, L.; Moe, R.; Chenette, D.; Schrijver, C.; Kilston, S.;
   Karovska, M.; Allen, R.; Brown, A.; Marzouk, J.; Murphy, N.; Walter, F.
Bibcode: 2004AAS...204.0810C
Altcode: 2004BAAS...36..791C
  The Stellar Imager (SI) is a `Vision' mission in the Sun-Earth
  Connection (SEC) Roadmap, conceived for the purpose of understanding
  the effects of stellar magnetic fields, the dynamos that generate
  them, and the internal structure and dynamics of the stars in
  which they exist. The ultimate goal is to achieve the best possible
  forecasting of solar/stellar magnetic activity and its impact on life
  in the Universe. The science goals of SI require an ultra-high angular
  resolution, at ultraviolet wavelengths, on the order of 100 micro-arcsec
  and thus baselines on the order of 0.5 km. These requirements call for
  a large, multi-spacecraft (&gt;20) imaging interferometer, utilizing
  precision formation flying in a stable environment, such as in a
  Lissajous orbit around the Sun-Earth L2 point. SI's resolution will
  make it an invaluable resource for many other areas of astrophysics,
  including studies of AGN's, supernovae, cataclysmic variables, young
  stellar objects, QSO's, and stellar black holes. <P />We present here
  an overview of the ongoing mission concept and technology development
  studies for SI. These studies are designed to refine the mission
  requirements for the science goals, define a Design Reference Mission,
  perform trade studies of selected major technical and architectural
  issues, improve the existing technology roadmap, and explore the
  details of deployment and operations, as well as the possible roles
  of astronauts and/or robots in construction and servicing of the
  facility. Additional information on SI mission concepts and technology
  can be found at URL: http://hires.gsfc.nasa.gov/ ∼si . <P />The SI
  Mission Concept Study is supported, in part, by grants from NASA-HQ
  through the 2003 Vision Mission NRA.

Title: Surprising Differences in the Winds and Mass-Loss Rates of
Two M-Giant Stars: Gamma Cru (M3.5III) and Mu Gem (M3III)
Authors: Carpenter, K. G.; Robinson, R. D.
Bibcode: 2003AAS...203.4902C
Altcode: 2003BAAS...35Q1284C
  We have assessed important parameters of the stellar winds of two very
  similar M giant stars, Gamma Cru (M3.5III) and Mu Gem (M3III), using
  high resolution HST/GHRS spectra and found surprising differences
  in the characteristics of their winds and in their total mass-loss
  rates. The wind parameters, including flow and turbulent velocities,
  the optical depth of the wind above the region of photon creation,
  and the mass-loss rate, have been estimated by fitting line profiles
  computed using the "Sobolev with Exact Integration" (SEI) radiative
  transfer code (Lamars et al. 1987), along with simple models of the
  outer atmospheric structure and wind. These computed profiles are fit
  to chromospheric emission lines which show self-absorptions produced
  by the photon-scattering winds of these stars. The SEI code has the
  advantage of being computationally fast and allows a great number
  of possible wind models to be examined. The analysis is iterative in
  nature: we specify estimates of the wind parameters, calculate line
  profiles for the Mg II (UV1) lines and a range of unblended Fe II
  lines (which have a wide range of wind opacities and therefore probe
  different heights in the atmosphere), compare the computed profiles
  with the observations, and modify the assumed wind properties until
  the predicted profiles match the observations over as many lines as
  possible.. Surprisingly, we find that the Gamma Cru wind exhibits a
  significantly higher terminal velocity, wind turbulence, and mass-loss
  rate than its fellow M-giant Mu Gem.

Title: Imaging terrestrial planets with a free-flying occulter and
space telescope: an optical simulation
Authors: Schultz, Alfred B.; Lyon, Richard G.; Kochte, Mark; Fraquelli,
   Dorothy A.; Bruhweiler, Frederick; Jordan, Ian J. E.; Carpenter,
   Kenneth G.; DiSanti, Michael A.; Miskey, Cherie; Rodrigue, Melodi;
   Fadali, M. S.; Skelton, Dennis; Hart, Helen M.; Cheng, Kwang-Ping
Bibcode: 2003SPIE.5170..262S
Altcode:
  In this manuscript, we further develop our concepts for the free-flying
  occulter space-based mission, the Umbral Missions Blocking Radiating
  Astronomical Sources (UMBRAS). Our optical simulations clearly show
  that an UMBRAS-like mission designed around a 4-m telescope and 10-m
  occulter could directly image terrestrial planets. Such a mission
  utilizing existing technology could be built and flown by the end of the
  decade. Moreover, many of the other proposed concepts for Terrestrial
  Planet Finder (TPF) could significantly benefit by using an external
  occulter. We present simultations for an optical design comprising a
  square aperture telescope plus square external occulter. We show that
  the entire diffraction pattern, which is propagated from occulter to
  telescope and through telescope to focal plane, may be characterized
  by two parameters, the Fresnel number and the ratio of the telescope
  diameter to the occulter width. Combining the effects of a square
  occulter with apodization provides a much more rapid roll-off in the
  PSF intensity between the diffraction spikes than may be achieved
  with an unapodized telecope aperture and occulter. We parameterize our
  results with respect to wavefront quality and compare them against other
  competing methods for exo-planet imaging. The combination of external
  occulter and apodization yields the required contrast in the region
  of the PSF essential for exo-planet detection. An occulter external
  to the telescope (i.e., in a separate spacecraft, as opposed to a
  classical coronagraph with internal occulter) reduces light scatter
  within the telescope by approximately 2 orders of magnitude. This is
  due to less light actually entering the telescope. Reduced scattered
  light significantly relaxes the constraints on the mirror surface
  roughness, especially in the mid-spatial frequencies critical for
  planet detection. This study, plus our previous investigations of
  engineering as well as spacecraft rendezvous and formation flying
  clearly indicates that the UMBRAS concept is very competitive with,
  or superior to, other proposed concepts for TPF missions.

Title: Imaging the Surfaces and Interiors of Other Stars: The Stellar
    Imager (SI) Mission Concept
Authors: Carpenter, K. G.; Lyon, R. G.; Schrijver, C. J.; Mundy,
   L. J.; Allen, R. J.; Rajagopal, J.
Bibcode: 2003csss...12.1091C
Altcode:
  The Stellar Imager (SI) is envisioned as a large (0.5 km diameter)
  space-based, UV-optical interferometer. It is designed to image surface
  features and, through asteroseismology, sub-surface structures of
  other stars and measure their spatial and temporal variations. These
  observations are needed to improve our understanding of the underlying
  dynamo process(es) and enable improved forecasting of solar/stellar
  activity and its impact on planetary climates and life. Schrijver and
  Carpenter (this volume) discuss the science goals of the mission in
  detail, while in this paper we discuss the performance requirements
  implied by the science goals and how these translate into specific
  design requirements on the mission architecture, and we present some
  preliminary visions for how the required observations (e.g., 1000 pixel,
  100 micro-arcsec resolution, UV-optical images of the surface of nearby
  dwarf stars) for this ambitious project might be obtained.

Title: Future Capabilities for Solar/Stellar Observations
Authors: Carpenter, K.; Hassler, D.; Berger, T.; Bastian, T.;
   Pallavicini, R.; Balachandran, S.
Bibcode: 2003csss...12..359C
Altcode:
  This session outlines the potential instrumental capabilities for the
  observation of cool stars and the Sun. The individual contributions
  cover space-based solar missions (Hassler), ground-based solar
  optical/IR instruments (Berger), solar-stellar radio capabilities
  (Bastian), space-based stellar missions (Carpenter), ground-based
  optical (Pallavicini) and infrared facilities (Balachandran) for
  stellar observations.

Title: Winds from ``Non-Coronal'' and ``Hybrid'' Stars Driven by
    MHD Waves
Authors: Airapetian, V. S.; Carpenter, K.; Ofman, L.
Bibcode: 2003AAS...202.3214A
Altcode: 2003BAAS...35..745A
  Observations obtained with IUE, HST and FUSE provide extensive data
  on atmospheric heating and wind dynamics for late-type luminous
  stars. The physical processes which drive winds in these stars are
  poorly understood, despite decades of study. In our previous study we
  have shown that observational signatures of winds can be interpreted
  by our model of winds driven by propagated Alfvén waves in stellar
  atmospheres and launched at a single frequency at the wind base
  (Airapetian et al. 2000). We extend our MHD calculations of winds
  from luminous late-type stars to include an Alfvén wave driver
  with a broad-band frequency range. The calculations are applied to
  ``non-coronal'' (α Tau) and ``hybrid'' (β Dra) giant stars to
  consistently reproduce the observed velocity profiles of the winds,
  its terminal velocity, the turbulent broadening of UV lines and mass
  loss rates. The nature of wind variability in luminous late-type stars
  is discussed. We also present the preliminary results of our first
  MHD and LTE radiative transfer calculations to model the UV spectra
  from the K5 giant, α Tau. <P />This research is supported by the NASA
  Research grant from GSFC No. NAG5-12869.

Title: A novel process to fabricate mirrors with very long radius
    and ultrasmooth surfaces
Authors: Chen, Peter C.; Carpenter, Kenneth G.; Romeo, Robert C.
Bibcode: 2003SPIE.4854...21C
Altcode:
  During the course of performing space flight qualification testing of
  composite mirrors at NASA GSFC, a serendipitious event was observed
  which, in retrospect, should have been obvious. Investigation of this
  phenomenon leads to a promising avenue towards the fabrication of large
  aperture precision spherical mirrors with very long radius of curvature
  (&gt;f/100). Such mirrors are required for future missions such as the
  Stellar Imager. We report on the observation and analysis of the event,
  optical measurements, and the development of associated active figure
  control systems.

Title: Simulating dilute-aperture imaging: The Stellar Imager
Authors: Rajagopal, Jayadev K.; Böker, Torsten; Allen, Ronald J.;
   Carpenter, Kenneth G.
Bibcode: 2003SPIE.4852..652R
Altcode:
  A number of proposed space missions for high resolution imaging
  at wavelengths ranging from IR to UV call for ``dilute-aperture''
  Fizeau-mode interferometers. We present here details of a software
  tool developed for high fidelity simulations of images obtained with
  such instruments. We show simulated images from the Stellar Imager, a
  mission concept being developed by NASA's GSFC to obtain high-resolution
  images of nearby stars in UV-optical wavelengths. Using the simulator,
  we study the capability of the proposed SI design to image stellar
  surfaces. We use the simulator to explore parameters of image quality
  such as resolution and dynamic range, and to evaluate proposed designs
  and the feasibility of science goals.

Title: Stellar Imager (SI) mission concept
Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Lyon, Richard
   G.; Mundy, Lee G.; Allen, Ronald J.; Armstrong, J. Thomas; Danchi,
   William C.; Karovska, Margarita; Marzouk, Joseph; Mazzuca, Lisa M.;
   Mozurkewich, David; Neff, Susan G.; Pauls, Thomas A.; Rajagopal,
   Jayadev K.; Solyar, Gregory; Zhang, Xiaolei
Bibcode: 2003SPIE.4854..293C
Altcode:
  The Stellar Imager (SI) is envisioned as a space-based, UV-optical
  interferometer composed of 10 or more one-meter class elements
  distributed with a maximum baseline of 0.5 km. It is designed to
  image stars and binaries with sufficient resolution to enable long-term
  studies of stellar magnetic activity patterns, for comparison with those
  on the sun. It will also support asteroseismology (acoustic imaging) to
  probe stellar internal structure, differential rotation, and large-scale
  circulations. SI will enable us to understand the various effects of
  the magnetic fields of stars, the dynamos that generate these fields,
  and the internal structure and dynamics of the stars. The ultimate
  goal of the mission is to achieve the best-possible forecasting
  of solar activity as a driver of climate and space weather on time
  scales ranging from months up to decades, and an understanding of the
  impact of stellar magnetic activity on life in the Universe. In this
  paper we describe the scientific goals of the mission, the performance
  requirements needed to address these goals, the "enabling technology"
  development efforts being pursued, and the design concepts now under
  study for the full mission and a possible pathfinder mission.

Title: UMBRAS: a matched occulter and telescope for imaging extrasolar
    planets
Authors: Schultz, Alfred B.; Jordan, Ian J.; Kochte, Mark; Fraquelli,
   Dorothy A.; Bruhweiler, Fred; Hollis, Jan M.; Carpenter, Kenneth
   G.; Lyon, Richard G.; DiSanti, Mike A.; Miskey, Cherie L.; Leitner,
   Jesse; Burns, Richard D.; Starin, Scott R.; Rodrigue, Melodi; Fadali,
   M. S.; Skelton, Dennis L.; Hart, Helen M.; Hamilton, Forrest C.;
   Cheng, Kwang-Ping
Bibcode: 2003SPIE.4860...54S
Altcode:
  We describe a 1-meter space telescope plus free-flying occulter craft
  mission that would provide direct imaging and spectroscopic observations
  of Jovian and Uranus-sized planets about nearby stars not detectable
  by Doppler techniques. The Doppler technique is most sensitive for
  the detection of massive, close-in extrasolar planets while the use
  of a free-flying occulter would make it possible to image and study
  stellar systems with planets comparable to our own Solar System. Such a
  mission with a larger telescope has the potential to detect earth-like
  planets. Previous studies of free-flying occulters reported advantages
  in having the occulting spot outside the telescope compared to a
  classical coronagraph onboard a space telescope. Using an external
  occulter means light scatter within the telescope is reduced due to
  fewer internal obstructions and less light entering the telescope and
  the polishing tolerances of the primary mirror and the supporting optics
  can be less stringent, thereby providing higher contrast and fainter
  detection limits. In this concept, the occulting spot is positioned
  over the star by translating the occulter craft, at distances of 1,000
  to 15,000 kms from the telescope, on the sky instead of by moving the
  telescope. Any source within the telescope field-of-view can be occulted
  without moving the telescope. In this paper, we present our current
  concept for a 1-m space telescope matched to a free-flying occulter,
  the Umbral Missions Blocking Radiating Astronomical Sources (UMBRAS)
  space mission. An UMBRAS space mission consists of a Solar Powered Ion
  Driven Eclipsing Rover (SPIDER) occulter craft and a matched (apodized)
  telescope. The occulter spacecraft would be semi-autonomous, with its
  own propulsion systems, internal power (solar cells), communications,
  and navigation capability. Spacecraft rendezvous and formation flying
  would be achieved with the aid of telescope imaging, RF or laser
  ranging, celestial navigation inputs, and formation control algorithms.

Title: The Stellar Imager (SI): An Ultra-High Angular Resolution
    Ultraviolet/Optical Observatory
Authors: Carpenter, K. G.; Lyon, R. G.; Schrijver, C. J.; Mundy, L.;
   Allen, R. J.; Rajagopal, J.
Bibcode: 2003ASPC..291..355C
Altcode: 2003hslf.conf..355C
  No abstract at ADS

Title: The Fizeau Interferometer Testbed
Authors: Zhang, Xiaolei; Carpenter, Kenneth G.; Lyon, Richard G.;
   Huet, Hubert; Marzouk, Joe; Solyar, Gregory
Bibcode: 2002astro.ph.12439Z
Altcode:
  The Fizeau Interferometer Testbed (FIT) is a collaborative effort
  between NASA's Goddard Space Flight Center, the Naval Research
  Laboratory, Sigma Space Corporation, and the University of Maryland. The
  testbed will be used to explore the principles of and the requirements
  for the full, as well as the pathfinder, Stellar Imager mission
  concept. It has a long term goal of demonstrating closed-loop control
  of a sparse array of numerous articulated mirrors to keep optical
  beams in phase and optimize interferometric synthesis imaging. In this
  paper we present the optical and data acquisition system design of the
  testbed, and discuss the wavefront sensing and control algorithms to
  be used. Currently we have completed the initial design and hardware
  procurement for the FIT. The assembly and testing of the Testbed will be
  underway at Goddard's Instrument Development Lab in the coming months.

Title: Steps Toward a Large Space-Based UV/Optical Fizeau
Interferometer: The GSFC Fizeau Interferometer Testbed (FIT)
Authors: Carpenter, K. G.; Lyon, R. G.; Mazzuca, L. M.; Solyar, G.;
   Marzouk, J.; Mundy, L. G.; Armstrong, J. T.; Zhang, X.
Bibcode: 2002AAS...201.8209C
Altcode: 2002BAAS...34.1240C
  Goddard Space Flight Center is pursuing the development of
  space-based, long-baseline (&gt;0.5km) UV-optical Fizeau imaging
  interferometers to enable the next major stride toward very high
  angular resolution astronomical observations. This effort includes
  the development and operation of the Fizeau Interferometry Testbed
  (FIT), in collaboration with the Naval Research Lab/NPOI, Univ. of
  MD, and Sigma Space Corporation. The FIT will be used to explore the
  principles of and requirements for the Stellar Imager (SI) mission
  concept (http://hires.gsfc.nasa.gov/ ~si) and other such Fizeau
  Interferometers/Sparse Aperture Telescope missions, leading in the end
  to the Planet Imager (PI), which is the ultimate goal of the current
  Origins Program. The primary goal of the FIT program is to demonstrate
  closed-loop control of mirrors (tip, tilt, piston, translation of
  array elements) and the overall system to keep the optical beams in
  phase and enable high quality imaging by a many-element (7-30) Fizeau
  Interferometric System. The FIT will also be used to assess various
  wavefront reconstruction and sensing and image reconstruction algorithms
  for utility and accuracy by application to real data generated by the
  Testbed. In this paper, we describe the design and goals of the system,
  provide a status report on its construction, and note our future
  plans. The FIT development is supported by NASA-ROSS/SARA grants to
  GSFC, UMD, and NRL and by internal GSFC R&amp;D funds.

Title: The Stellar Imager (SI): An UV-Optical Interferometer in Space
Authors: Zhang, X.; Carpenter, K.; Schrijver, C.
Bibcode: 2002AAS...200.6102Z
Altcode: 2002BAAS...34..744Z
  The Stellar Imager (SI) is envisioned as a space-based, UV-optical
  interferometer composed of 10 or more one-meter class mirrors
  distributed with a maximum baseline of 0.5 km and providing a resolution
  of 60 micro-arcseconds at 1550 A. It will image stars and binaries
  with one hundred to one thousand resolution elements on their surfaces
  and enable long-term studies of stellar magnetic activity patterns and
  their evolution with time, for comparison with those on the sun. It will
  also sound their interiors through asteroseismology to image internal
  structure, differential rotation, and large-scale circulations. SI will
  enable us to understand the various effects of magnetic fields of stars,
  the dynamos that generate them, and the internal structure and dynamics
  of the stars in which they exist. The ultimate goal is to achieve the
  best-possible forecasting of solar activity on times scales ranging
  up to decades, and an understanding of the impact of stellar magnetic
  activity on life in the Universe. With substantial improvements in
  normal-incidence mirror coatings for the EUV, the concept could be
  extended into that shorter wavelength regime as well. Fitting naturally
  within the NASA long-term time line, SI complements defined missions,
  and with them will show us entire other solar systems, from the central
  star to their orbiting planets.

Title: What Is Happening at Spectral Type F5 in Hyades F Stars?
Authors: Böhm-Vitense, Erika; Robinson, Richard; Carpenter, Kenneth;
   Mena-Werth, Jose
Bibcode: 2002ApJ...569..941B
Altcode:
  Aiming at a better understanding of the mechanisms heating the
  chromospheres, transition regions, and coronae of cool stars, we study
  ultraviolet, low-resolution Hubble Space Telescope/Space Telescope
  Imaging Spectrograph spectra of Hyades main-sequence F stars. We
  study the B-V dependence(s) of the chromospheric and transition layer
  emission line fluxes and their dependences on rotational velocities. We
  find that the transition layer emission line fluxes and also those of
  strong chromospheric lines decrease steeply between B-V=0.42 and 0.45,
  i.e., at spectral type F5, for which the rotational velocities also
  decrease steeply. The magnitude of the line-flux decrease increases
  for lines of ions with increasing degree of ionization. This shows
  that the line-flux decrease is not due to a change in the surface
  filling factor but rather due to a change of the relative importance
  of different heating mechanisms. For early F stars with B-V&lt;0.42
  we find for the transition layer emission lines increasing fluxes
  for increasing vsini, indicating magnetohydrodynamic heating. The
  vsini dependence is strongest for the high-ionization lines. On
  the other hand, the low chromospheric lines show no dependence on
  vsini, indicating acoustic shock heating for these layers. This also
  contributes to the heating of the transition layers. The Mg II and Ca
  II lines show decreasing fluxes for increasing vsini, as long as vsini
  is less than ~40 km s<SUP>-1</SUP>. The coronal X-ray emission also
  decreases for increasing vsini, except for vsini larger than ~100 km
  s<SUP>-1</SUP>. We have at present no explanation for this behavior. For
  late F stars the chromospheric lines show vsini dependences similar to
  those observed for early F stars, again indicating acoustic heating
  for these layers. We were unable to determine the vsini dependence
  of the transition layer lines because of too few single star
  targets. The decrease of emission line fluxes at the spectral type
  F5, with steeply decreasing vsini, indicates, however, a decreasing
  contribution of magnetohydrodynamic heating for the late F stars. The
  X-ray emission for the late F stars increases for increasing vsini,
  indicating magnetohydrodynamic heating for the coronae of the late F
  stars, different from the early F stars. Based on observations with
  the NASA/ESA Hubble Space Telescope obtained at the Space Telescope
  Science Institute, which is operated by the Association of Universities
  for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.

Title: Estimation of Mass-Loss Rates for M Giants from UV Emission
    Line Profiles
Authors: Carpenter, K. G.; Robinson, R. D.
Bibcode: 2001AAS...199.9205C
Altcode: 2001BAAS...33.1441C
  The photon-scattering winds of M giants produce absorption features
  in the strong chromospheric emission lines. These provide us with an
  opportunity to assess important parameters of the wind, including
  flow and turbulent velocities, the optical depth of the wind above
  the region of photon creation, and the star's mass-loss rate. We
  have used the Lamers et al. (1987) Sobolev with Exact Integration
  (SEI) radiative transfer code, along with simple models of the outer
  atmospheric structure and wind, to determine the wind characteristics of
  two M-giant stars, γ Cru (M3.4) and μ Gem (M3IIIab). The SEI code has
  the advantage of being computationally fast and allows a great number
  of possible wind models to be examined. The analysis procedure involves
  specifying wind parameters and then using the program to calculate
  line profiles for the Mg II (UV1) lines and a range of unblended Fe II
  lines. These lines have a wide range of wind opacities and therefore
  probe different heights in the atmosphere. The assumed wind properties
  are iterated until the predicted profiles match the observations
  over as many lines as possible. We present estimates of the wind
  parameters for these stars and offer a comparison to wind properties
  previously-derived for low-gravity K stars using the same technique.

Title: Free-flying Occulters for Use with Space Telescopes
Authors: Kochte, M.; Schultz, A. B.; Jordan, I.; Hamilton, F.;
   Bruhweiler, F.; DiSanti, M. A.; Burns, R. D.; Carpenter, K.; Hollis,
   J. M.; Leitner, J.; Lyon, R. G.; Starin, S.; Fadali, M. S.; Rodrigue,
   M.; Skelton, D. L.; Hart, H. M.
Bibcode: 2001AAS...199.4501K
Altcode: 2001BAAS...33Q1367K
  We summarize a free-flying occulter proposal that was submitted to NASA
  in response to NRA-01-OSS-04. Free-flying occulters in association
  with space telescopes have been proposed for nearly four decades to
  detect and study extrasolar planets. External occulters reduce the
  magnitude differences between a planet and the host star; light scatter
  within the telescope is reduced resulting from fewer obstructions and
  optical surfaces; and any instrument onboard the telescope, including
  spectrometers, can be used to study extrasolar planets. We conclude with
  a mission concept for an optimized optical 1-m space telescope with a
  small external occulter. Both craft could be launched from a single
  launch vehicle and placed in a 1-AU fall-away orbit or at Earth-Sun
  L2. Jovian planets around stars within 10 parsecs could be studied,
  and a search for sub-Jovian planets around the nearest handful of stars
  could be performed. Approximately 80% of the telescope time would be
  available for projects not associated with the external occulter such
  as gravitational lensing and planetary transit surveys.

Title: Goddard High Resolution Spectrograph Observations of NGC 4151
Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.;
   Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone,
   D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.;
   Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Snow, M.; Ake, T. B.
Bibcode: 2001AJ....121.2999B
Altcode:
  Goddard High Resolution Spectrograph observations of the nucleus of
  the bright, nearby Seyfert galaxy NGC 4151 are presented andbriefly
  described.

Title: AB Dor in '94. I. Hubble Space Telescope Goddard High
    Resolution Spectrogaph Observations of the Quiescent Chromosphere
    of an Active Star
Authors: Brandt, J. C.; Heap, S. R.; Walter, F. M.; Beaver, E. A.;
   Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura,
   M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.;
   Smith, A. M.; Trafton, L. M.; Weymann, R. J.; Norman, D.; Redfield, S.
Bibcode: 2001AJ....121.2173B
Altcode:
  We analyze Hubble Space Telescope/Goddard High Resolution Spectrograph
  spectra of AB Doradus, the prototypical, ultrarapidly rotating K
  dwarf. We observed chromospheric (Mg II) and transition-region (C
  II, Si IV, C IV, and N V) lines periodically throughout the stellar
  rotation period and provide a low-dispersion stellar atlas of 78
  emission lines. The quiescent line profiles of the chromospheric
  and transition-region lines show narrow cores superposed on very
  broad wings. The broad wings of the Mg II k and h lines and of
  the transition-region lines can be explained by emission from gas
  corotating with the star and extending out to near the Keplerian
  corotation radius (2.8 stellar radii). While this is not a unique
  solution, it is consistent with previous studies of Hα emission,
  which are naturally explained by large corotating prominences. We find
  no evidence for rotational modulation of the emission-line fluxes. The
  density diagnostics suggest that the transition region is formed at
  constant pressure, with an electron density of 2-3×10<SUP>12</SUP>
  cm<SUP>-3</SUP> at a temperature of 3×10<SUP>4</SUP> K. The electron
  pressure is about 100 times larger than that for the quiet Sun. The
  emission-measure distribution shows a minimum between logT=5 and
  5.5. The Mg II line exhibits three interstellar absorption components
  along the 15 pc line of sight. We identify the lowest velocity component
  with the G Cloud, but the other components are not identified with
  any interstellar clouds previously detected from other lines of sight.

Title: Mg II Emission Lines of Hyades F Stars
Authors: Böhm-Vitense, Erika; Mena-Werth, Jose; Carpenter, Kenneth
   G.; Robinson, Richard D.
Bibcode: 2001ApJ...550..457B
Altcode:
  With the Hubble Space Telescope (HST) we have observed Hyades
  F stars, using the Space Telescope Imaging Spectrograph (STIS),
  in order to get more information about the heating mechanism(s)
  for the chromospheres and transition layers and their dependence
  on rotation and age. In this paper we study the Mg II lines at 2800
  Å. We include earlier observations with the International Ultraviolet
  Explorer (IUE) satellite. The Mg II emission lines become observable
  for B-V&gt;0.3. The emission line fluxes increase steeply until
  B-V~0.40. For single stars there is a steep decrease in flux between
  B-V=0.41 and B-V=0.44, similar to the behavior of the Ca II emission
  line cores. For larger B-V the Mg II emission line fluxes again
  increase, but much more slowly than for the Ca II lines. Generally,
  the low point of the emission is reached between B-V=0.43 and B-V=0.45,
  i.e., similar to the Ca II emission cores. For the Hyades F stars there
  appears to be a difference between the emissions for single stars and
  those for binaries. We find that for Hyades stars with surface line
  fluxes larger than 10<SUP>6</SUP> ergs cm<SUP>-2</SUP> s<SUP>-1</SUP>
  the emission line fluxes decrease with increasing vsini. For smaller
  fluxes they may increase with increasing vsini. We have only three
  stars that perhaps show this. We study the flux ratios of the Mg II
  k and h lines at 2795.7 and 2802.5 Å in order to determine where
  the lines fall on the curve of growth. For the earliest F stars
  studied here the ratio is close to 2, as expected for optically thin
  lines. Generally, it seems that the optical depths in the line centers
  are less than 10. There remain problems in understanding the size of
  the line widths. We discuss the interpretation of the Wilson-Bappu
  effect. For the Hyades F stars there is a strong dependence of the
  line width on the effective temperature. Based on observations with
  the NASA/ESA Hubble Space Telescope obtained at the Space Telescope
  Science Institute, which is operated by the Association of Universities
  for Research in Astronomy. Incorporated, under NASA contract NAS5-26555.

Title: The Stellar Imager (SI) mission concept
Authors: Carpenter, Kenneth G.; Neff, Susan G.; Schrijver, Carolus J.;
   Allen, Ronald J.; Rajagopal, Jay
Bibcode: 2001LIACo..36..177C
Altcode: 2001fomi.conf..177C
  The Stellar Imager (SI) is envisioned as a space-based, UV-optical
  interferometer composed of 10 or more one-meter class elements
  distributed with a maximum baseline of 0.5 km. It will image stars
  and binaries with one hundred to one thousand resolution elements on
  their surface and enable long-term studies of stellar magnetic activity
  patterns and their evolution with time, for comparison with those on
  the sun. It will also sound their interiors through asteroseismology
  to image internal structure, differential rotation, and large-scale
  circulations. SI will enable us to understand the various effects
  of magnetic fields of stars, the dynamos that generate them, and the
  internal structure and dynamics of the stars in which they exist. The
  ultimate goal is to achieve the best-possible forecasting of solar
  activity on times scales ranging up to decades, and an understanding
  of the impact of stellar magnetic activity on astrobiology and
  life in the Universe. The road to that goal will revolutionize our
  understanding of stars and stellar systems, the building blocks of the
  Universe. Fitting naturally within the NASA and ESA long-term time
  lines, SI complements defined missions, and with them will show us
  entire other solar systems, from the central star to their orbiting
  planets. In this paper we will describe the scientific goals of the
  mission, the performance requirements needed to address those goals,
  and the design concepts now under study.

Title: Far-UV Echelle Spectroscopy of Arcturus with HST STIS (CD-ROM
Directory: contribs/ayres)
Authors: Ayres, T. R.; Brown, A.; Harper, G. M.; Bennett, P. D.;
   Linsky, J. L.; Carpenter, K. G.; Robinson, R. D.
Bibcode: 2001ASPC..223.1079A
Altcode: 2001csss...11.1079A
  No abstract at ADS

Title: Estimation of Mass-Loss Rates from Emission Line Profiles in
the UV Spectra of Cool Stars (CD-ROM Directory: contribs/carpente)
Authors: Carpenter, K. G.; Robinson, R. D.; Harper, G. M.
Bibcode: 2001ASPC..223.1591C
Altcode: 2001csss...11.1591C
  No abstract at ADS

Title: Coordinated Optical, Radio and EUV Observations of a Flare
on YZ CMi (CD-ROM Directory: contribs/robinson)
Authors: Robinson, R. D.; Airapetian, V.; Slee, O. B.; Mathioudakis,
   M.; Carpenter, K. G.
Bibcode: 2001ASPC..223.1151R
Altcode: 2001csss...11.1151R
  No abstract at ADS

Title: AB Dor in '94: I. HST/GHRS Observations of the Quiescent
    Chromosphere of an Active Star
Authors: Brandt, J. C.; Heap, S. R.; Walter, F. M.; Beaver, E. A.;
   Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura,
   M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.;
   Smith, A. M.; Trafton, L. M.; Weymann, R. J.; Norman, D.; Redfield, S.
Bibcode: 2000astro.ph.12487B
Altcode:
  We analyze HST/GHRS spectra of AB Doradus, the prototypical
  ultra-rapidly rotating K dwarf. We observed chromospheric (Mg II)
  and transition region (C II, Si IV, C IV, and N V) lines periodically
  throughout the stellar rotation period, and provide a low dispersion
  stellar atlas of 78 emission lines. The quiescent line profiles of the
  chromospheric and transition region lines show narrow cores superposed
  on very broad wings. The broad wings of the Mg II k &amp; h lines and
  of the transition region lines can be explained by emission from gas
  co-rotating with the star and extending out to near the Keplerian
  co-rotation radius (2.8 stellar radii). While this is not a unique
  solution, it is consistent with previous studies of H-alpha emission
  that are naturally explained by large co-rotating prominences. We
  find no evidence for rotational modulation of the emission line
  fluxes. The density diagnostics suggest that the transition region is
  formed at constant pressure, with an electron density 2-3 E12 /cm^3
  at a temperature of 30,000 K. The electron pressure is about 100 times
  larger than that for the quiet Sun. The emission measure distribution
  shows a minimum between log(T) = 5 and 5.5. The Mg II line exhibits
  three interstellar absorption components along the 15 pc line of
  sight. We identify the lowest velocity component with the G cloud,
  but the other components are not identified with any interstellar
  clouds previously detected from other lines of sight.

Title: Ultraviolet Emission Lines in BA and Non-BA Giants
Authors: Böhm-Vitense, Erika; Carpenter, Kenneth G.; Robinson,
   Richard D.
Bibcode: 2000ApJ...545..992B
Altcode:
  With the Hubble Space Telescope (HST) and the Goddard High Resolution
  Spectrograph we have observed four barium and three weak barium stars
  in the ultraviolet spectral region, together with two nonpeculiar giant
  standard stars. An additional suspected Ba star was observed with HST
  and the Space Telescope Imaging Spectrograph. In the H-R diagram,
  three of the observed Ba stars lie on the same evolutionary tracks
  as the Hyades giants. Using International Ultraviolet Explorer (IUE)
  spectra of previously studied giants together with our HST spectra,
  we investigate whether the chromospheric and transition layer
  emission-line spectra of the Ba stars are different from those of
  nonpeculiar giants and from those of giants with peculiar carbon and/or
  nitrogen abundances. Except for the Ba star HD 46407 and the suspected
  Ba star HD 65699, the Ba star and mild Ba star emission-line fluxes are,
  for a given effective temperature and for a given luminosity, lower
  than those for the nonpeculiar giants observed with IUE. In comparison
  with the HST-observed standard stars, the C IV λ1550-to-C II λ1335
  line flux ratios are smaller, but not necessarily so in comparison
  with all IUE-observed nonpeculiar giants. However, the C IV-to-C II
  line flux ratios for the Ba stars decrease with increasing carbon
  abundances. This shows that the energy balance in the lower transition
  layer is influenced by the carbon abundance. The temperature gradient
  appears to be smaller in the C II line-emitting region. There does not
  seem to be a difference in chromospheric electron densities for the
  Ba and non-Ba stars, though this result is rather uncertain. Based on
  observations with the NASA/ESA Hubble Space Telescope obtained at the
  Space Telescope Science Institute, which is operated by the Association
  of Universities for Research in Astronomy, Inc., under NASA contract
  NAS 5-26555.

Title: The Stellar Imager (SI) Mission Concept
Authors: Carpenter, K. G.; Schrijver, C. J.
Bibcode: 2000AAS...197.1410C
Altcode: 2000BAAS...32.1426C
  The Stellar Imager (SI) is envisioned as a space-based, UV-optical
  interferometer composed of 10 or more one-meter class elements
  distributed with a maximum baseline of 0.5 km. It will image stars
  and binaries with one hundred to one thousand resolution elements on
  their surface and enable long-term studies of stellar magnetic activity
  patterns and their evolution with time, for comparison with those on
  the sun. It will also sound their interiors through asteroseismology
  to image internal structure, differential rotation, and large-scale
  circulations. SI will enable us to understand the various effects
  of magnetic fields of stars, the dynamos that generate them, and the
  internal structure and dynamics of the stars in which they exist. The
  ultimate goal is to achieve the best-possible forecasting of solar
  activity on times scales ranging up to decades, and an understanding of
  the impact of stellar magnetic activity on astrobiology and life in the
  Universe. The road to that goal will revolutionize our understanding of
  stars and stellar systems, the building blocks of the Universe. Fitting
  naturally within the NASA long-term time line, SI complements defined
  missions, and with them will show us entire other solar systems,
  from the central star to their orbiting planets.

Title: A Dream of a Mission: Stellar Imager and Seismic Probe
Authors: Carpenter, K. G.; Schrijver, C. J.
Bibcode: 2000AAS...196.3207C
Altcode: 2000BAAS...32..721C
  The Stellar Imager and Seismic Probe (SISP) is a mission to understand
  the various effects of magnetic fields of stars, the dynamos that
  generate them, and the internal structure and dynamics of the stars in
  which they exist. The ultimate goal is to achieve the best-possible
  forecasting of solar activity on times scales ranging up to decades,
  and an understanding of the impact of stellar magnetic activity on
  astrobiology and life in the Universe. The road to that goal will
  revolutionize our understanding of stars and stellar systems, the
  building blocks of the Universe. SISP will zoom in on what today
  - with few exceptions - we only know as point sources, revealing
  processes never before seen, thus providing a tool to astrophysics as
  fundamental as the microscope is to the study of life on Earth. SISP
  is an ultraviolet aperture-synthesis imager with 8-10 telescopes
  with meter-class apertures, and a central hub with focal-plane
  instrumentation that allows spectrophotometry in passbands as narrow
  as a few Angstroms up to hundreds of Angstroms. SISP will image stars
  and binaries with one hundred to one thousand resolution elements
  on their surface, and sound their interiors through asteroseismology
  to image internal structure, differential rotation, and large-scale
  circulations; this will provide accurate knowledge of stellar structure
  and evolution and complex transport processes, and will impact numerous
  branches of (astro)physics ranging from the Big Bang to the future of
  the Universe. Fitting naturally within the NASA long-term time line,
  SISP complements defined missions, and with them will show us entire
  other solar systems, from the central star to their orbiting planets.

Title: A dream of a mission: the stellar imager and seismic probe.
Authors: Schrijver, C. J.; Carpenter, K. G.
Bibcode: 2000BAAS...32R.828S
Altcode:
  No abstract at ADS

Title: A dream of a mission: the Stellar Imager and Seismic Probe
Authors: Schrijver, C. J.; Carpenter, K. G.
Bibcode: 2000SPD....31.0298S
Altcode: 2000BAAS...32..828S
  The Stellar Imager and Seismic Probe (SISP) is a mission to understand
  the various effects of magnetic fields of stars, the dynamos that
  generate them, and the internal structure and dynamics of the stars in
  which they exist. The ultimate goal is to achieve the best-possible
  forecasting of solar activity on times scales ranging up to decades,
  and an understanding of the impact of stellar magnetic activity on
  astrobiology and life in the Universe. The road to that goal will
  revolutionize our understanding of stars and stellar systems, the
  building blocks of the Universe. SISP represents an advance in image
  detail of several hundred times over the Hubble Space Telescope. SISP
  will zoom in on what today - with few exceptions - we only know as
  point sources, revealing processes never before seen, thus providing
  a tool to astrophysics as fundamental as the microscope is to the
  study of life on Earth. SISP is an ultraviolet aperture-synthesis
  imager with 8-10 telescopes with meter-class apertures, and a central
  hub with focal-plane instrumentation that allows spectrophotometry in
  passbands as narrow as a few Angstroms up to hundreds of Angstroms. SISP
  will image stars and binaries with one hundred to one thousand
  resolution elements on their surface, and sound their interiors through
  asteroseismology to image internal structure, differential rotation,
  and large-scale circulations; this will provide accurate knowledge
  of stellar structure and evolution and complex transport processes,
  and will impact numerous branches of (astro)physics ranging from the
  Big Bang to the future of the Universe. Fitting naturally within the
  NASA long-term time line, SISP complements defined missions, and with
  them will show us entire other solar systems, from the central star
  to their orbiting planets.

Title: Do All BA II Stars Have White Dwarf Companions?
Authors: Böhm-Vitense, Erika; Carpenter, Kenneth; Robinson, Richard;
   Ake, Tom; Brown, Jeffery
Bibcode: 2000ApJ...533..969B
Altcode:
  With the Hubble Space Telescope (HST) and the Goddard High Resolution
  Spectrograph (GHRS) we have observed four barium stars, three mild
  barium stars, and one weak G-band star in the ultraviolet spectral
  region. One barium star was observed with HST and the Space Telescope
  Imaging Spectrograph (STIS). The aim was to check the hypothesis
  that all these peculiar stars have white dwarf (WD) companions,
  which at their asymptotic giant branch phase transferred mass with
  peculiar element abundances to the present barium and CH peculiar
  stars. Assuming that the ultraviolet continua of the cool giants,
  including the barium stars, are generated in their chromospheres and
  that the relations between the continua and the emission lines created
  in the chromospheres and transition layers are similar in field giants
  and barium stars, we found that, indeed, most of our target barium and
  weak barium stars appear to have excess flux in the UV when compared
  to standard giant stars. For most of the stars the excess flux can
  be attributed to WD companions with temperatures between 10,000 and
  12,000 K, if the WD mass is about 0.6 M<SUB>solar</SUB>. Cooling times
  for the WDs were derived from their effective temperatures and model
  calculations by M. Wood. The calculated cooling times are longer than
  the lifetimes of the barium stars on the giant branch. For our target
  stars the mass transfer therefore happened while they were still on
  the main sequence. For two of the mild barium stars and one or perhaps
  two barium stars the derived cooling times for the WD companions come
  out to be longer than the total evolutionary times of the barium stars
  as calculated by Schaller et al. If our derivations are correct (the
  error bars are rather large) then either evolutionary models with larger
  convective overshoot have to be used for the barium stars or the cooling
  times of the white dwarfs have to be revised downward. Possibly an
  additional (as yet unknown) cooling mechanism has to be considered? The
  weak G-band star HD 165634, which has a carbon underabundance of about
  a factor of 10, also appears to have a WD companion. We discuss the
  implications of this very low carbon abundance. Based on observations
  with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope
  Science Institute, which is operated by the Association of Universities
  for Research in Astronomy. Incorporated, under NASA contract NAS5-26555.

Title: Critical Complements: Progress on the Orbit of T Mon
Authors: Evans, N. R.; Carpenter, K.; Robinson, R.; Massa, D.;
   Wahlgren, G. M.; Vinkó, J.; Szabados, L.
Bibcode: 2000ASPC..203..246E
Altcode: 2000IAUCo.176..246E; 2000ilss.conf..246E
  A preliminary orbit has been derived for the high luminosity, 27-d
  classical Cepheid T Mon. Velocities for the hot companion have been
  measured from an HST GHRS spectrum and 3 IUE spectra. The companion
  velocities are inconsistent with binary orbital motion and it is
  likely that the companion is itself a short period binary. The HST
  spectrum also shows that the companion is a chemically peculiar star,
  probably magnetic.

Title: Winds from Luminous Late-Type Stars. I. The Effects of
    Nonlinear Alfvén Waves
Authors: Airapetian, V. S.; Ofman, L.; Robinson, R. D.; Carpenter,
   K.; Davila, J.
Bibcode: 2000ApJ...528..965A
Altcode:
  We present the results of magnetohydrodynamic (MHD) modeling of winds
  from luminous late-type stars using a 2.5-dimensional, nonlinear MHD
  computer code. We assume that the wind is generated within an initially
  hydrostatic atmosphere and is driven by torsional Alfvén waves
  generated at the stellar surface. Two cases of atmospheric topology
  are considered: case I has longitudinally uniform density distribution
  and isotropic radial magnetic field over the stellar surface, and case
  II has an isotropic, radial magnetic field with a transverse density
  gradient, which we refer to as an ``atmospheric hole.'' We use the
  same set of boundary conditions for both models.The calculations
  are designed to model a cool luminous star, for which we assume an
  initial hydrostatic pressure scale height of 0.072 R<SUB>*</SUB>,
  an Alfvén wave speed of 92 km s<SUP>-1</SUP> at the surface, and a
  wave period of 76 days, which roughly corresponds with the convective
  turnover time. For case I the calculations produce a wind with terminal
  velocity of ~22 km s<SUP>-1</SUP> and a mass loss rate comparable to the
  expected value of 10<SUP>-6</SUP> M<SUB>solar</SUB> yr<SUP>-1</SUP>. For
  case II we predict a two-component wind: a fast (25 km s<SUP>-1</SUP>)
  and relatively dense wind outside of the atmospheric hole and a slow
  (15 km s<SUP>-1</SUP>), rarefied wind inside of the hole.

Title: Toward an Orbit for the High-Luminosity Cepheid T Monocerotis
Authors: Evans, Nancy Remage; Carpenter, Kenneth; Robinson, Richard;
   Massa, Derck; Wahlgren, Glenn M.; Vinko, Jozsef; Szabados, Laszlo
Bibcode: 1999ApJ...524..379E
Altcode:
  We have obtained new velocities of the long-period Cepheid T Mon
  from the ground and velocities of its hot companion with the Hubble
  Space Telescope (HST) and the International Ultraviolet Explorer
  (IUE). Although observations do not cover a full orbit, both the
  maximum and minimum orbital velocities have now been obtained. We
  present a preliminary orbit and discuss the uncertainties in the
  orbital parameters. The velocities for the companion appear to be
  inconsistent with binary orbital motion, and it is likely that the
  companion is itself a binary in a short-period orbit. The HST spectrum
  of the companion shows that it is a chemically peculiar star, probably
  magnetic. Because it is coupled with the more massive Cepheid, it must
  be very close to the zero-age main sequence. The well-determined mass
  function from the preliminary orbit implies that the inclination of
  the long-period system is close to 90°. <P />Based on observations
  made with the NASA/ESA Hubble Space Telescope, obtained at the Space
  Telescope Science Institute, which is operated by the Association
  of Universities for Research in Astronomy, Inc., under NASA contract
  NASA-26555

Title: GHRS Observations of Cool, Low-Gravity Stars. V. The Outer
    Atmosphere and Wind of the Nearby K Supergiant λ Velorum
Authors: Carpenter, Kenneth G.; Robinson, Richard D.; Harper, Graham
   M.; Bennett, Philip D.; Brown, Alexander; Mullan, Dermott J.
Bibcode: 1999ApJ...521..382C
Altcode:
  UV spectra of λ Velorum taken with the Goddard High Resolution
  Spectrograph (GHRS) on the Hubble Space Telescope are used to probe the
  structure of the outer atmospheric layers and wind and to estimate the
  mass-loss rate from this K5 Ib-II supergiant. VLA radio observations at
  λ=3.6 cm are used to obtain an independent check on the wind velocity
  and mass-loss rate inferred from the UV observations. Parameters
  of the chromospheric structure are estimated from measurements of
  UV line widths, positions, and fluxes and from the UV continuum flux
  distribution. The ratios of optically thin C II] emission lines indicate
  a mean chromospheric electron density of logN<SUB>e</SUB>~8.9+/-0.2
  cm<SUP>-3</SUP>. The profiles of these lines indicate a chromospheric
  turbulence (v<SUB>0</SUB>~25-36 km s<SUP>-1</SUP>), which greatly
  exceeds that seen in either the photosphere or wind. The centroids
  of optically thin emission lines of Fe II and of the emission
  wings of self-reversed Fe II lines indicate that they are formed in
  plasma approximately at rest with respect to the photosphere of the
  star. This suggests that the acceleration of the wind occurs above
  the chromospheric regions in which these emission line photons are
  created. The UV continuum detected by the GHRS clearly traces the
  mean flux-formation temperature as it increases with height in the
  chromosphere from a well-defined temperature minimum of 3200 K up to
  about 4600 K. Emission seen in lines of C III] and Si III] provides
  evidence of material at higher than chromospheric temperatures in the
  outer atmosphere of this noncoronal star. The photon-scattering wind
  produces self-reversals in the strong chromospheric emission lines,
  which allow us to probe the velocity field of the wind. The velocities
  to which these self-absorptions extend increase with intrinsic line
  strength, and thus height in the wind, and therefore directly map
  the wind acceleration. The width and shape of these self-absorptions
  reflect a wind turbulence of ~9-21 km s<SUP>-1</SUP>. We further
  characterize the wind by comparing the observations with synthetic
  profiles generated with the Lamers et al. Sobolev with Exact Integration
  (SEI) radiative transfer code, assuming simple models of the outer
  atmospheric structure. These comparisons indicate that the wind in
  1994 can be described by a model with a wind acceleration parameter
  β~0.9, a terminal velocity of 29-33 km s<SUP>-1</SUP>, and a mass-loss
  rate~3×10<SUP>-9</SUP> M<SUB>solar</SUB> yr<SUP>-1</SUP>. Modeling
  of the 3.6 cm radio flux observed in 1997 suggests a more slowly
  accelerating wind (higher β) and/or a higher mass-loss rate than
  inferred from the UV line profiles. These differences may be due to
  temporal variations in the wind or from limitations in one or both
  of the models. The discrepancy is currently under investigation. <P
  />Based on observations with the NASA/ESA Hubble Space Telescope,
  which is operated by the Association of Universities for Research in
  Astronomy, Inc., under NASA contract NAS 5-26555.

Title: STIS UV Atlas of the Red Giant Arcturus(1)
Authors: Ayres, T. R.; Brown, A.; Harper, G. M.; Bennett, P. D.;
   Linsky, J. L.; Carpenter, K. G.; Robinson, R. D.
Bibcode: 1999AAS...194.6701A
Altcode: 1999BAAS...31..930A
  The Space Telescope Imaging Spectrograph (STIS) conducted a series
  of observations of the archetype ``noncoronal'' red giant Arcturus
  (HD 124897; alpha Boo; K1 III) on 24 August 1998, 17--23 UT. The STIS
  program was the result of a failed cycle 5 pointing, which could not
  be rescheduled during the abbreviated cycle 6, and was carried over
  to cycle 7. Three grating settings---E230H (t_exp= 1340 s), E230M
  (2493 s), and E140M (5208 s)---covered the ultraviolet spectrum
  from 1150--2850 Angstroms, at resolutions between R ~ 4*E(4) -
  1*E(5) , with essentially no gaps. The resulting spectrograms are
  stunning. The resolution is very high, as is the S/N; the spectral
  coverage is broad and comprehensive. The far-UV interval (1150--1700
  Angstroms) is a rich emission line spectrum, dominated by the broad
  resonance transitions of atomic hydrogen (lambda 1215) and oxygen
  (lambda 1305 triplet). There are numerous narrow emissions, mostly
  from low-excitation species such as Si I, Fe II, and fluoresced bands
  of carbon monoxide. Surprisingly, high-excitation species---Si IV
  (lambda 1393: 6*E(4) K) and C IV (lambda 1548: 1*E(5) K)---are present
  as well (as seen in the earlier ``failed'' GHRS spectra). The mid-UV
  (1700--2600 Angstroms) shows additional emission lines, particularly [C
  II] and [Si II] in the 2325 Angstroms region; the photospheric continuum
  rises strongly toward the longer wavelengths. The 2600--2850 Angstroms
  interval is mostly a photospheric absorption spectrum, although the
  bright chromospheric emission doublet of Mg II lords over the 2800
  Angstroms region. We present a comprehensive spectral atlas based on
  our reductions of the STIS echellograms. We discuss the processing
  strategies, line identifications, and some of the preliminary results
  from our analysis of this windy, noncoronal giant. (1) This work was
  supported by grants GO-06066.01-94A from STScI, and NAG5-3226 from
  NASA. Observations were from the NASA/ESA HST, collected at the STScI,
  operated by AURA, under contract NAS5-26555.

Title: A Search for Microflaring Activity on DME Flare
    Stars. II. Observations of YZ Canis Minoris
Authors: Robinson, R. D.; Carpenter, K. G.; Percival, J. W.
Bibcode: 1999ApJ...516..916R
Altcode:
  We report on time-series photometric observations of the dM4.5e flare
  star YZ Canis Minoris obtained in 1993 November with the High Speed
  Photometer on board the Hubble Space Telescope. The data consist of five
  30 minute time sequences with a sampling rate of 0.01 s that were taken
  through the F240W filter (centered at 240 nm with an 80 nm width). At
  these wavelengths the stellar photospheric background is small,
  so relatively small flares can be detected. The observations show a
  stellar background of 120 counts s<SUP>-1</SUP> on which are superposed
  54 flare events ranging in integrated flux from 2.0×10<SUP>28</SUP>
  to 3.0×10<SUP>30</SUP> ergs, as well as longer term variations with an
  amplitude of up to 50% of the average continuum intensity and timescales
  ranging from several minutes to hours. A statistical analysis of this
  background suggests that it may be composed of unresolved microflaring
  activity that has an energy distribution considerably steeper than
  that deduced for the larger flare events. This is consistent with
  previous observations as well as the self-organized criticality and
  reconnecting current sheet flare theories. These results are compared
  with data from the dM8e flare star CN Leonis, which was obtained
  earlier with the same experimental setup. CN Leo has both a smaller
  stellar background and a lower flare occurrence rate than YZ CMi. The
  fact that CN Leo also has a quiescent X-ray flux that is less than
  10% of the YZ CMi emission suggests a link between chromospheric and
  coronal heating. <P />Based on observations with the NASA/ESA Hubble
  Space Telescope, which is operated by the Association of Universities
  for Research in Astronomy, Inc., under NASA contract NAS5-26555.

Title: A Goddard High Resolution Spectrograph Atlas of Echelle
    Observations of the HGMN Star chi LUPI
Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess,
   A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.;
   Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith,
   A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Proffitt, C. R.;
   Wahlgren, G. M.; Johansson, S. G.; Nilsson, H.; Brage, T.; Snow, M.;
   Ake, T. B.
Bibcode: 1999AJ....117.1505B
Altcode:
  Observations of the ultra-sharp-lined, chemically peculiar star chi
  Lupi taken by the Goddard High Resolution Spectrograph in echelle mode
  are presented. Thirty-six intervals of the spectral region between
  1249 and 2688 Å are covered with resolving powers in the range
  75,000-93,000. Line identifications are provided, and the observed
  spectra are compared with synthetic spectra calculated using the
  SYNTHE program and associated line lists with changes to the line
  lists. The significance of these spectra for the chi Lupi Pathfinder
  Project and the closely related atomic physics effort is discussed in
  a companion paper.

Title: Lines of OIV and SIV in the Goddard High-Resolution
Spectrograph spectrum of RR Tel: constraints on atomic data
Authors: Harper, G. M.; Jordan, C.; Judge, P. G.; Robinson, R. D.;
   Carpenter, K. G.; Brage, T.
Bibcode: 1999MNRAS.303L..41H
Altcode:
  High signal-to-noise ratio spectra of RR Tel obtained at medium
  resolution with the Goddard High-Resolution Spectrograph (GHRS) on the
  Hubble Space Telescope (HST) are used to test available atomic data for
  the OIV 2s^22p ^2P-2s2p^2 ^4P multiplet (UV 0.01). The fine-structure
  intervals of the 2s2p^2 ^4P term given by Moore (1983) appear to need
  revision. The flux ratios of lines within multiplet UV (0.01), which
  have a common upper level, depend only on transition probabilities. The
  observed flux ratio of lines from the ^4P_3/2 level differs from that
  predicted by theory, but this difference cannot be attributed to a
  blend with a line of SIV]. At the electron densities in the RR Tel
  nebula, other flux ratios give information on the relative electron
  excitation rates between the ^2P and ^4P fine-structure levels. Using
  the collision strengths calculated by Zhang, Graziani &amp; Pradhan,
  the rate to the ^4P_5/2 level, relative to the rates to the other J
  states, appears to be underestimated by ~ 10 per cent, which is within
  the expected uncertainty of 20 per cent. We also discuss the SIV 3s^23p
  ^2P-3s3p^2 ^4P multiplet.

Title: Echelle Spectroscopy of Interstellar Absorption toward MU
    Columbae with the Goddard High Resolution Spectrograph
Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.;
   Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone,
   D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.;
   Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Howk, J. C.; Snow,
   M.; Ake, T. B.; Sembach, K. R.
Bibcode: 1999AJ....117..400B
Altcode:
  Goddard High Resolution Spectrograph echelle-mode observations of
  the interstellar absorption lines of Mg II, Si IV, C IV, and N V
  toward mu Columbae (HD 38666) are presented. The observations have a
  spectral resolution of 3.5 km s^-1 and signal-to-noise ratios (S/Ns)
  of 20-200. The mu Col sight line (l=237.3d, b=-27.1d, d=0.40 kpc,
  z=-0.18 kpc) extends though the Local Bubble and the warm neutral,
  warm ionized, and hot ionized phases of the interstellar medium
  (ISM). The high-ionization column densities toward mu Col are
  log N(Si IV)=12.16+/-0.05, log N(C IV)=12.88+/-0.02, and logN(N
  V)=11.8-12.3. Profile fits to Copernicus satellite measures of O VI
  absorption toward mu Col yield log N(O VI)=13.82+/-0.01 and b=38.7
  km s^-1. This implies N(C IV)/N(O VI)=0.11+/-0.01, which is typical
  of the values found for the hot ISM of the Galactic disk. The O VI
  profile is twice as broad as the C IV and N V profiles, even though
  these species have roughly similar average velocities. Some of the C
  IV, N V, and O VI absorption toward mu Col may occur at the interface
  of the Local Cloud and Local Bubble, although additional contributions
  to these ions probably also occur in more distant gas along the sight
  line. A substantial part of the Si IV absorption likely arises in warm
  photoionized gas in an H II region surrounding mu Col. The profile
  width differences among the high-ionization lines of C IV, N V, and
  O VI could be produced if the line of sight passes through a highly
  evolved supernova remnant. The observations for mu Col and for other
  stars observed at high resolution with the GHRS reveal that multiple
  gas types (warm and hot) contribute to the absorption by the highly
  ionized atoms along both nearby and distant sight lines. Disentangling
  the relative contributions from the different gas types requires
  high-resolution and high-S/N observations. The Mg II observations,
  combined with a solar Mg reference abundance, imply that the Mg
  depletion toward mu Col is -0.31 dex. As observed for other sight
  lines through the warm neutral medium, the gas-phase observations of
  Mg, when combined with results for Fe and Si, suggest that Mg and Fe
  are more deficient from the gas phase than one would expect if these
  elements are only contained in silicate dust grains.

Title: Winds and mass-loss from evolved, low-gravity cool stars.
Authors: Carpenter, Kenneth G.; Robinson, Richard D.
Bibcode: 1999NewAR..43..471C
Altcode:
  We summarize results from several programs utilizing the Goddard High
  Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST) to
  study winds and mass-loss from evolved, low-gravity cool stars. We have
  found that: (i) the photons for thermally and fluorescently excited
  UV emission lines are created below the region of wind acceleration,
  (ii) the self-reversals in optically thick emission lines indicate an
  outflowing wind with mean velocities of 9-25 km/s, (iii) the profiles
  of optically thin emission lines indicate a mean chromospheric
  macroturbulence of 24-35 km/s, anisotropically distributed along
  the radial-tangential directions, (iv) significant emission from
  hot material (≈10 <SUP>5</SUP> K) is seen in both non-coronal and
  hybrid stars to the right of the Linsky-Haisch dividing line, (v)
  the weakness of Fe II emission lines in the carbon stars, combined
  with the presence of the Fe I 2807 Å feature only in carbon stars,
  suggests that the ionization fraction of iron is significantly lower in
  the outer atmospheres of carbon stars than in O-rich stars, and (vi)
  Fe II line profile variations indicate changes in mass-loss rate and
  wind opacity on a timescale of several years in two typical late-type,
  low-gravity stars.

Title: The outer atmosphere of Tau - II. Fluorescent lines
Authors: McMurry, A. D.; Jordan, C.; Carpenter, K. G.
Bibcode: 1999MNRAS.302...48M
Altcode:
  The Goddard High Resolution Spectrograph (GHRS) on the Hubble Space
  Telescope has been used to observe α Tau (K5 III). The resulting
  spectra contain many sharp fluorescent lines. Most of these have been
  identified as lines of Fe ii, Ca ii and H<SUB>2</SUB>, radiatively
  excited by H Lyα. The chromospheric model developed in an accompanying
  paper has been used to calculate the fluxes in these lines. The Ca ii
  lines have been modelled with a full radiative transfer calculation,
  but the Fe ii and H<SUB>2</SUB> systems are more complex and, for
  these, a simpler calculation has been made. Overall, the trend in the
  Fe ii line fluxes provides evidence for a multicomponent model of the
  atmosphere, a chromosphere with intrusions of hotter material or vice
  versa. The hotter material could be in shocks propagating through
  the chromosphere. Comparisons of the observed and calculated fluxes
  of individual lines of Fe ii show that some atomic data need to be
  improved. The analysis of the H<SUB>2</SUB> lines is restricted by
  a lack of suitable molecular data. The two observed Ca ii lines are
  reproduced to within a factor of 2.

Title: Estimation of Mass-Loss Rates from Emission Line Profiles in
    the UV Spectra of Cool Stars
Authors: Carpenter, K. G.; Robinson, R. D.; Harper, G. M.
Bibcode: 1999STIN...0027505C
Altcode:
  The photon-scattering winds of cool, low-gravity stars (K-M giants and
  supergiants) produce absorption features in the strong chromospheric
  emission lines. This provides us with an opportunity to assess important
  parameters of the wind, including flow and turbulent velocities,
  the optical depth of the wind above the region of photon creation,
  and the star's mass-loss rate. We have used the Lamers et al. Sobolev
  with Exact Integration (SEI) radiative transfer code along with simple
  models of the outer atmospheric structure to compute synthetic line
  profiles for comparison with the observed line profiles. The SEI
  code has the advantage of being computationally fast and allows a
  great number of possible wind models to be examined. We therefore
  use it here to obtain initial first-order estimates of the wind
  parameters. More sophisticated, but more time-consuming and resource
  intensive calculations will be performed at a later date, using the
  SEI-deduced wind parameters as a starting point. A comparison of
  the profiles over a range of wind velocity laws, turbulence values,
  and line opacities allows us to constrain the wind parameters,
  and to estimate the mass-loss rates. We have applied this analysis
  technique (using lines of Mg II, 0 I, and Fe II) so far to four stars:
  the normal K5-giant alpha Tau, the hybrid K-giant gamma Dra, the K5
  supergiant lambda Vel, and the M-giant gamma Cru. We present in this
  paper a description of the technique, including the assumptions which
  go into its use, an assessment of its robustness, and the results of
  our analysis.

Title: The Chromosphere, Wind, and Mass-Loss Rate of lambda Velorum
    (K5 Ib) as Revealed by UV Emission Line Profiles
Authors: Carpenter, K. G.; Robinson, R. D.; Harper, G. M.; Bennett,
   P. D.; Brown, A.; Mullan, D. J.
Bibcode: 1998AAS...193.4502C
Altcode: 1998BAAS...30Q1317C
  The Goddard High Resolution Spectrograph (GHRS) on the HST has been
  used to acquire high-quality UV spectra of the nearby K-supergiant
  lambda Velorum. These spectra contain a wide variety of chromospheric
  emission lines, many of which are self-reversed by wind absorption,
  and thus allow us to probe the structure of both the chromosphere
  and wind. The observed line widths, positions, and fluxes indicate a
  chromosphere with a mean log n_e ~ 8.9 +/- -0.2 cm(-3) , a turbulence
  (indicated by line cores with ~ 25 km s(-1) Doppler widths) greatly
  in excess of the photospheric value, and no general systematic flows
  (i.e. the wind acceleration appears to occur above the region of
  photon creation). We compare synthetic Fe II line profiles from the
  approximate Lamers et al. (1987) Sobelev with Exact Integration (SEI)
  method, and from an exact comoving frame CRD calculation, with the
  observations. The width and shape of the wind self-absorptions implies
  a terminal velocity of 29--33 km s(-1) , and a wind turbulence of ~
  9-21 km s(-1) . We find that the wind in the 1994 GHRS observations
  can be described by a model with an acceleration parameter beta ~ 0.9
  and a mass-loss rate of ~ 3 x 10(-9) M<SUB>sun</SUB> yr(-1) . However,
  this model is not consistent with the VLA 3.6 cm radio continuum flux
  observed in 1997.

Title: The Mass of the Cepheid Binary V636 Scorpii
Authors: Böhm-Vitense, E.; Evans, N. R.; Carpenter, K.; Albrow,
   Michael D.; Cottrell, P. L.; Robinson, R.; Beck-Winchatz, B.
Bibcode: 1998ApJ...505..903B
Altcode:
  The mass-luminosity relation for Cepheids depends on the degree of
  mixing in their main-sequence progenitors. Masses of Cepheids can be
  inferred by using different aspects of pulsation theory. These methods
  have in the past led to diverging results, showing that something was
  wrong in either evolution theory or pulsation theory or both. For some
  binary Cepheids dynamical masses, which are independent of pulsation and
  evolution theories, can be determined. V636 Sco is one of a handful of
  Cepheid binaries whose companions are bright enough in the ultraviolet
  that orbital radial velocities can be measured. We have here attempted
  to determine the radial velocity of the companion V636 Sco B to the
  Cepheid V636 Sco A by means of two Hubble Space Telescope (HST) spectra
  taken at phases of minimum and maximum Cepheid orbital velocities. The
  ratio of the orbital velocity of the companion and the Cepheid (which
  is the inverse of their mass ratio) came out to be 1.25 +/- 0.17. V636
  Sco B has a spectral type B9.5 V, for which we expect a stellar mass
  of 2.5 M<SUB>⊙</SUB>. For the Cepheid we thus determine a mass
  of 3.1 +/- 0.4 M<SUB>⊙</SUB>, which is surprisingly low. If true,
  such a low mass would indicate an extremely large amount of excess
  mixing, which is very unlikely. <P />We discuss the likely possibility
  that V636 Sco B may itself be a binary with an unseen secondary,
  in which case the mass derived from the two measurements discussed
  above is not correct. Although the error limits for the mass of each
  Cepheid are rather large, the combined mass-luminosity relation for
  all Cepheids studied by us so far by means of HST spectra indicates
  excess mixing corresponding to core convective overshoot by 0.25 to
  about 0.5 pressure scale height in the main-sequence progenitors of
  the Cepheids. <P />Based on observations made with the NASA/ESA Hubble
  Space Telescope, obtained at the Space Telescope Science Institute,
  which is operated by the Association of Universities for Research in
  Astronomy, Inc., under NASA contract NASS-26555.

Title: Toward a Mass for the High Luminosity Cepheid T MON
Authors: Evans, Nancy Remage; Robinson, Richard D.; Carpenter,
   Kenneth G.; Vinko, Jozsef; Massa, Derck; Wahlgren, Glenn M.
Bibcode: 1998AAS...192.8204E
Altcode: 1998BAAS...30.1155E
  The long period (27(d) ) Cepheid T Mon was shown by Coulson (1983,
  MNRAS, 203, 925) to have orbital motion. A full orbit has not yet been
  observed since the first velocities nearly a century ago. However, the
  ratio of the orbital velocity changes during the last decade provide the
  mass ratio between the Cepheid and its hot companion. We have obtained
  new ground-based velocities of the Cepheid which constrain the orbital
  velocity amplitude. To measure the companion velocities, we have IUE
  high resolution spectra and also a Hubble Space Telescope Goddard High
  Resolution Spectrograph spectrum (1840 to 1880 Angstroms). Use of the
  new data to constrain the mass of the Cepheid will be discussed.

Title: Goddard High-Resolution Spectrograph Observations of Cool
    Low-Gravity Stars. IV. A Comparison of the K5 III stars α Tauri
    and γ Draconis
Authors: Robinson, Richard D.; Carpenter, Kenneth G.; Brown, Alexander
Bibcode: 1998ApJ...503..396R
Altcode:
  The Goddard High-Resolution Spectrograph (GHRS) has observed the K5 III
  star α Tau in the 2330 Å region on three separate occasions. These
  spectra show marked changes with time, with the UV continuum varying
  by a factor of 2, and with the emission lines changing in flux by 30%
  or more, with the amount of change dependent upon the opacity of the
  line. The variations suggests a restructuring of the atmosphere rather
  than simply a change in the surface area covered by chromospheric
  material. Surprisingly, there was no detectable change in the
  chromospheric turbulence on timescales of hours or years. On average,
  the lower part of the atmosphere was found to be fairly static, with
  a slight infall of 1-2 km s<SUP>-1</SUP>. At higher altitudes, probed
  by observation of the stronger Fe II lines as well as of the O I (UV 2)
  and Mg II (UV 1) resonance lines, there is evidence for the acceleration
  of a slow wind, similar to that seen in the M giants γ Cru and μ
  Gem. This wind is much less massive than for the later type giants,
  however, since its effects are seen in only the most optically thick
  of the Fe II lines. Comparison of the α Tau observations with similar
  data for the K5 III hybrid star γ Dra shows remarkable similarity in
  the photosphere and lower chromosphere. Both stars have pronounced
  UV continua, identical turbulences and chromospheric densities, and
  very similar line fluxes and profiles for all lines formed in the
  lower chromosphere, including C II], Co I, Si II], and Fe II. A deep
  exposure near 1500 Å also shows the first evidence for hot plasma
  in the atmosphere of α Tau through the detection of the C IV (UV 1)
  doublet with a surface flux about 30% of that observed in γ Dra. Most
  of the evidence for the stellar wind is in the Mg II (UV 1) and O I
  (UV 2) resonance lines. Modeling these lines using the Sobolev with
  Exact Integration (SEI) radiative transfer code shows that the wind in
  γ Dra accelerates faster and reaches a higher terminal velocity than
  does the wind in α Tau. However, the wind turbulent velocity in γ Dra
  is only about one-third of the value seen in α Tau. We conclude that
  the observations support the suggestion by Judge &amp; Stencel that the
  processes that heat the chromosphere are distinct from those that drive
  the stellar winds. <P />Based on observations with the NASA/ESA Hubble
  Space Telescope, which is operated by the Association of Universities
  for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Title: An Ultraviolet Spectral Atlas of 10 Lacertae Obtained with
    the Goddard High Resolution Spectrograph on the Hubble Space Telescope
Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess,
   A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.;
   Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith,
   A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Snow, M.; Ake,
   T. B.; Hogen, R. H.
Bibcode: 1998AJ....116..941B
Altcode:
  Observations of the narrow-lined O-type star 10 Lacertae taken with the
  Goddard High Resolution Spectrograph in 1992 November are presented. The
  spectra cover the wavelength range 1181-1777 Å with a resolution of
  15 km s^-1 and signal-to-noise ratio greater than 100:1. Absorption
  lines arising in the interstellar medium, the photosphere, and the
  stellar wind are identified and discussed.

Title: Large Variations in the Winds of Single Cool Giants: λ
    Velorum and γ Crucis
Authors: Mullan, D. J.; Carpenter, K. G.; Robinson, R. D.
Bibcode: 1998ApJ...495..927M
Altcode:
  UV spectra of the ``noncoronal'' single K supergiant λ Vel and of
  the single M giant γ Cru obtained with IUE and the Hubble Space
  Telescope at various epochs indicate that the profiles of many lines
  formed in the wind exhibit striking alterations in shape with time. We
  parameterize the wind profiles in terms of an empirical optical depth
  τ<SUB>emp</SUB> by reflecting the red wing about line center and
  comparing the reflected intensity with that of the blue wing. In the λ
  Vel wind the terminal velocity v<SUB>∞</SUB> was found to be close
  to 40 km s<SUP>-1</SUP> in 1978, 1982, and 1994, but was at least 20
  km s<SUP>-1</SUP> greater in 1990. The faster wind in 1990 also had
  a total optical depth that was a factor of 2-6 times greater than at
  the other epochs. <P />Based on observations with the NASA/ESA Hubble
  Space Telescope, which is operated by the Association of Universities
  for Research in Astronomy, Inc., under NASA contract NAS 5-26555,
  and on observations with the International Ultraviolet Explorer.

Title: Classical Cepheid Masses: U Aquilae
Authors: Evans, Nancy Remage; Böhm-Vitense, Erika; Carpenter, Kenneth;
   Beck-Winchatz, Bernhard; Robinson, Richard
Bibcode: 1998ApJ...494..768E
Altcode:
  We have obtained medium-resolution spectra (λ/Δλ ~ 20,000) of the hot
  binary companion to the classical Cepheid U Aql with the Goddard High
  Resolution Spectrograph on the Hubble Space Telescope (HST). These have
  been used to determine the orbital velocity amplitude. Combining this
  with the orbital velocity amplitude of the Cepheid from the ground-based
  orbit and the mass of the companion inferred from its spectral type, we
  measure a mass of the Cepheid of 5.1 +/- 0.7 M<SUB>⊙</SUB>. We discuss
  the full sample of Cepheids for which we have determined masses with HST
  (S Mus, V350 Sgr, Y Car, and U Aql) and also SU Cyg (mass from IUE). The
  HST masses are in agreement with the luminosities predicted by recent
  evolutionary tracks with moderate overshoot. This comparison, however,
  may be altered by reassessment of Cepheid distances based on Hipparcos
  parallaxes. <P />Based on observations made with the NASA/ESA Hubble
  Space Telescope, obtained at the Space Telescope Science Institute,
  which is operated by the Association of Universities for Research in
  Astronomy, Inc., under NASA contract NASA-26555.

Title: On Chromospheric Heating Mechanisms of ``Basal Flux'' Stars
Authors: Judge, P. G.; Carpenter, K. G.
Bibcode: 1998ApJ...494..828J
Altcode:
  Several pieces of evidence have been pieced together over recent years
  to support the notion that the chromospheric emission measured from
  stars with convection zones results in part from the upward propagation
  and dissipation of acoustic waves. One argument, based on a statistical
  analysis of available UV data of such stars across the H-R diagram,
  suggests the presence of an omnipresent ``basal'' level of chromospheric
  heating, which has been postulated as resulting from nonlinear acoustic
  wave heating. <P />However, with few exceptions, no studies have been
  made that test more directly the intrinsically dynamic nature of this
  shock-heating mechanism. Therefore, in order to search for more direct
  signatures of such upward-propagating shock waves in lines of C II,
  we examined Goddard High-Resolution Spectrograph spectra of several
  evolved stars that have ``basal'' levels of activity. No evidence is
  found to support the presence of such waves as a dominant component
  of the heating mechanism. Instead, behavior reminiscent of the solar
  transition region is seen, suggesting a magnetic heating mechanism
  for these stars. <P />We conclude that upward-propagating shock waves
  do not dominate the observed radiative losses from chromospheres of
  stars exhibiting typical ``basal'' behavior, and we suggest that the
  nonmagnetic origin of the basal components of all convective stars
  must be called into question. New solar data from the SUMER instrument
  on SOHO also suggest problems with the acoustic-wave interpretation,
  although further work is warranted. <P />In the course of this work,
  we also found a simple explanation for previously noted discrepancies
  between calculated and observed ratios of C II lines in the spectrum
  of α Ori. <P />Based on observations with the NASA/ESA Hubble Space
  Telescope, which is operated by the Association of Universities for
  Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Title: The Goddard High Resolution Spectrograph: Post-COSTAR
    Characteristics
Authors: Robinson, R. D.; Ake, T. B.; Lindler, D. J.; Heap, S. R.;
   Carpenter, K. G.; Leckrone, D. S.; Maran, S. P.; Smith, A. M.; Brandt,
   J. C.; Beaver, E. A.; Boggess, A.; Ebbets, D. C.; Hutchings, J. B.;
   Jura, M.; Linsky, J. L.; Savage, B. D.; Trafton, L. M.; Walter, F. M.;
   Weymann, R. J.
Bibcode: 1998PASP..110...68R
Altcode:
  We review changes to the characteristics of the Goddard High Resolution
  Spectrograph (GHRS) which resulted from the installation of the
  Corrective Optics Space Telescope Axial Replacement (COSTAR) on the
  Hubble Space Telescope. The introduction of two new optical elements
  into the light path altered the spectral distribution of the light,
  decreasing the amount of light striking the instrument by about 30%
  at wavelengths greater than 1200 Å and effectively eliminated all
  radiation at wavelengths less than 1130 Å. However, at the longer
  wavelengths the improved focus offset this loss when the Large Science
  Aperture (LSA) was used and increased the overall throughput of the
  Small Science Aperture (SSA) by a factor of 2. The improved focus also
  enhanced the spectral resolution of LSA observations and improved the
  ability of the instrument to observe in crowded fields.

Title: The Mass of the Classical Cepheid V350 SGR
Authors: Evans, N. R.; Bohm-Vitense, E.; Beck-Winchatz, B.; Carpenter,
   K.; Robinson, R.
Bibcode: 1998ASPC..143..313E
Altcode: 1998sigh.conf..313E
  No abstract at ADS

Title: The Structure of the Outer Atmosphere and Wind of lambda Vel
Authors: Carpenter, Kenneth G.
Bibcode: 1998IAUS..191P.206C
Altcode:
  The Goddard High Resolution Spectrograph (GHRS) on the Hubble Space
  Telescope (HST) has been used to acquire high-quality UV spectra of the
  nearby K-supergiant lambda Vel, a star most likely in an evolutionary
  stage either immediately preceeding or just entering the AGB. These
  spectra contain a wide variety of chromospheric emission lines, as
  well as a strong chromospheric continuum, and thus allow us to probe
  conditions in the the atmospheric region within which the stellar wind
  and associated mass-loss are initiated. In addition, the profiles of
  many of these emission lines are influenced by absorption occurring
  within the wind and are thus good diagnostics of the radial structure of
  that wind. Comparison of synthetic and observed spectra allows estimates
  of the wind turbulence, acceleration, opacity, and mass-loss rate. We
  present a summary of our analysis of these spectra, including: 1)
  measurements of temperature, turbulence, and flow velocity versus height
  in the chromosphere and wind, and 2) estimates of the mass-loss rate. It
  is our hope that these observations will provide powerfull constraints
  on theoretical models of chromospheric heating, wind acceleration,
  and mass-loss in this and other red giant and supergiant stars.

Title: The Mass of the Beat Cepheid Y Carinae
Authors: Bohm-Vitense, E.; Beck-Winchatz, B.; Evans, N. R.; Carpenter,
   K. G.; Robinson, R.
Bibcode: 1998ASPC..143..317B
Altcode: 1998sigh.conf..317B
  No abstract at ADS

Title: Fluorescence in the Chromosphere of alpha Tau (K5 III)
Authors: McMurry, A. D.; Jordan, C.; Carpenter, K. G.; Robinson, R. D.
Bibcode: 1998ASPC..154.1293M
Altcode: 1998csss...10.1293M
  The Goddard High Resolution Spectrograph (GHRS) on the Hubble Space
  Telescope has been used to obtain spectra of alpha Tau covering many
  parts of the uv spectrum between 1200AA and 2000AA. Here we concentrate
  on the region between 1320AA and 1390AA, which is covered by 2 medium
  resolution exposures. Most of the lines appearing in these spectra have
  been identified, including 2 bands of fluorescent CO lines. Preliminary
  modelling of these CO lines has been carried out, and the results are
  compared with the observations.

Title: The Mass of the Classical Cepheid S MUSCAE
Authors: Evans, N. R.; Bohm-Vitense, E.; Beck-Winchatz, B.; Carpenter,
   K.; Robinson, R.
Bibcode: 1998ASPC..143..309E
Altcode: 1998sigh.conf..309E
  No abstract at ADS

Title: The Dynamical and Beat Masses of the Beat Cepheid Y Carinae
Authors: Bohm-Vitense, E.; Evans, N. R.; Carpenter, K.; Winchatz,
   B. Beck-; Morgan, S.; Robinson, R.
Bibcode: 1998ASPC..135..280B
Altcode: 1998hcsp.conf..280B
  The mass-luminosity relation for Cepheids depends on the degree
  of excess mixing in their main sequence progenitors. The mass
  determination for Cepheids with their known luminosities therefore
  determines the degree of excess mixing in massive main sequence
  stars. We have determined the dynamical mass of several Cepheids with
  blue companions. Here we discuss the beat Cepheid Y Carinae. By means
  of HST, GHRS spectra we measured the radial velocity of the B9.5 V
  companion Y Car B at phases near minimum and maximum orbital radial
  velocities. The orbital velocity amplitude ratio between the Cepheid
  and the hot companion and thereby the mass ratio comes out to be 1.51
  0.5, leading to a mass of 3.8 1 1.2 solar masses. Taking the 3.8 solar
  masses at face value this indicates excess mixing corresponding to
  convective overshoot by about 1 pressure scale height, (see Bertelli et
  al.1986), but the error limits are too large for a firm conclusion. The
  beat masses, determined from the period ratios for the beat Cepheids,
  have puzzled astronomers for a long time (see Cox 1980) because they
  came out around 1 to 2 solar masses, when the Cox-Tabor opacities
  were used for the model calculations. Moskalik et al.(1992) showed
  that beat masses around 4 to 5 solar masses can now be derived, if
  the new OPAL opacities are used instead. With the determination of
  the dynamical mass for Y Car A we can now check the validity of the
  OPAL opacities more quantitatively than was possible before. Using the
  model calculations incorporating the OPAL opacities, and the observed
  effective temperature of Y Carinae we determine for its beat mass a
  possible range of 3.75 &lt; M/Ms &lt; 4.0, in very good agreement with
  the dynamical mass. This supports the validity of the OPAL opacities,
  and also supports the conclusion about the high degree of excess mixing
  in the main sequence progenitor of Y Carinae A.

Title: Cool Stars
Authors: Carpenter, K. G.
Bibcode: 1998ASPC..143...67C
Altcode: 1998sigh.conf...67C
  No abstract at ADS

Title: Winds and Mass-Loss from Evolved, Low-Gravity Cool Stars
Authors: Carpenter, K. G.; Robinson, R. D.
Bibcode: 1998HiA....11..378C
Altcode:
  No abstract at ADS

Title: Searching for the Cause of Hybrid Star Activity
Authors: Robinson, Richard D.; Carpenter, Kenneth G.; Brown, Alexander
Bibcode: 1998ASPC..154.1307R
Altcode: 1998csss...10.1307R
  UV spectra for a wide range of chromospheric diagnostics have been
  obtained for the non-coronal giant alpha Tau and the `hybrid' star
  gamma Dra using the Goddard High Resolution Spectrograph. These stars
  have very similar spectral types and are very close to one another in
  mass, luminosity, size, effective temperature and gravity. A detailed
  comparison shows that the photosphere and chromosphere of the stars
  are very similar. The two stars show the same level of UV continuum
  emission and chromospheric turbulence and have Fe 2 emission profiles
  which are nearly identical. The amount of transition region plasma,
  as measured by the C 4 surface flux, is also nearly the same. The winds
  of these two stars, however, are significantly different. Preliminary
  models based on the O 1 (UV 2) and Mg 2 (UV 1) profiles show that
  the wind for alpha Tau has a terminal velocity of ~30 km s^{-1} and
  a much slower acceleration than the wind of gamma Dra, which has a
  terminal velocity of ~65 km s^{-1}. However, despite the different wind
  properties, the mass loss rate from these two stars is very similar.

Title: Two-Component Winds from Luminous Late-Type Stars
Authors: Airapetian, V. S.; Offman, L.; Robinson, R.; Carpenter, K.;
   Davila, J.
Bibcode: 1998BAAS...30..760A
Altcode:
  We present the results of a magnetohydrodynamic (MHD) simulation
  of winds from luminous late-type stars using a 2.5D, non-linear MHD
  computer code. In this simulation we assume that the wind is generated
  within a hydrostatic atmosphere with an initial isothermal pressure
  scale height of 0.072 R<SUB>star</SUB> and a radial magnetic field. We
  also assume a transverse density gradient which we we refer to as a
  ``chromospheric hole''. Tortional Alfven waves are generated at the
  stellar surface by a forcing function having a single frequency, which
  is comparable to the turn-over frequency of convective cells in giant
  stars. To ensure that we are accurately assessing the terminal velocity
  of the wind, we carried out the calculations to a height of 20 stellar
  radii and a time period of more than 180 Alfven transit times, which
  ensures that a steady state has been reached. In the higher density
  (low Alfven velocity) regions outside of the ``chromospheric hole'' the
  Alfven waves are freely propagating. Ponderomotive forces associated
  with these waves drive radial, compressive motions and contribute to
  stellar wind acceleration. The compressive motions then excite slow
  magnetosonic waves which non-linearly steepen into solitary waves that
  propagate on top of a background flow similar to the case of solar
  coronal holes. This produces a fast (40-80 km/s) and relatively dense
  component of the wind. In the lower density ``chromospheric hole''
  region the Alfven waves are strongly reflected and produce an outflow
  with both radial and azimuthal velocities which are ~ 10% of the local
  Alfven speed. This component of the wind is slow ( ~ 10-30 km/s) and
  less dense than the wind initiated outside of the hole. Depending on
  the magnetic topology in the atmosphere of a luminous late - type
  star, we may therefore expect either one (fast) or two components
  to the wind. Our results are consistent with recent observations of
  two discrete components to the wind in the K5 III hybrid star gamma
  Dra. These components were detected in the Mg II h and k resonance lines
  and had velocities of 67 and 30 km/s, with the higher velocity component
  having a mass loss rate which is 10 times that of the slower speed wind.

Title: Atmospheric Dynamics of Luminous Late-Type Stars
Authors: Airapetian, V. S.; Ofman, L.; Robinson, R. D.; Carpenter,
   K.; Davila, J.
Bibcode: 1998ASPC..154.1569A
Altcode: 1998csss...10.1569A
  We present first results of magnetohydrodynamic (MHD) calculations of
  winds from luminous late-type stars using an existing, 2.5D, non-linear
  MHD code recently developed by Ofman &amp; Davila (e.g., Ofman &amp;
  Davila 1997). We assume that the wind is initiated in a hydrostatic
  atmosphere with an isothermal pressure scale height of 0.072 R* and a
  ``chromospheric hole'' modeled by a transverse density structure and
  a radial magnetic field. To ensure that we are accurately assessing
  the terminal velocity of the wind, we carried out the calculations
  to a height of 20 stellar radii. We find that in the higher density
  (low Alfven velocity) regions outside of the ``chromospheric hole'' the
  Alfven waves are freely propagating. Ponderomotive forces associated
  with these waves drive radial, compressive motions and contribute to
  stellar wind acceleration. The compressive motions then excite slow
  magnetosonic waves which non-linearly steepen into solitary waves that
  propagate on top of a background flow. This situation is similar to
  solar coronal hole models. In the lower density ``chromospheric hole''
  region the Alfven wave are strongly reflected, and produce a substantial
  outflow, with both radial and azimuthal velocities approaching the
  local Alfven speed. Our results are in qualitative agreement with
  observational signatures of winds in cool, luminous late-type stars.

Title: HST Observations of Carbon Stars
Authors: Carpenter, Kenneth G.; Robinson, R. D.; Johnson, H. R.
Bibcode: 1998ASPC..154.1578C
Altcode: 1998csss...10.1578C
  Ultraviolet spectra obtained with the Goddard High Resolution
  Spectrograph (GHRS) on the HST of the carbon stars TX Psc, TW Hor,
  and UU Aur are presented and compared with each other and with spectra
  of the oxygen-rich cool giants mu Gem and 30 Her. For TX Psc, we
  discuss the inferred outer atmospheric flow and turbulent velocities,
  the relative and absolute strength of emission from C 2 and Fe 2,
  the ionization fraction of iron, and variations of its spectrum with
  time. We also discuss two fluorescence processes operating in the
  atmospheres of carbon stars and compare in detail the Mg 2 profiles
  seen in both carbon and O-rich stars.

Title: Digging Deeper in the Coronal Graveyard
Authors: Ayres, Thomas R.; Brown, Alexander; Harper, G. M.; Bennett,
   P. D.; Linsky, J. L.; Carpenter, K. G.; Robinson, R. D.
Bibcode: 1997ApJ...491..876A
Altcode:
  Soft X-ray detections of stellar coronae (T ~ 10<SUP>6</SUP> K) are
  rare in the giant branch redward of ~K1 III. We have conducted a less
  direct--but more sensitive--search using the Hubble Space Telescope
  Goddard High-Resolution Spectrograph to probe for far-ultraviolet
  proxies of the hot coronal gas in representative ``noncoronal''
  red giants. In every target so far examined, we find weak but
  statistically significant Si IV emission, as well as, commonly,
  C IV and, in some cases, N V. Si IV is not affected by the CNO
  anomalies produced by the first dredge-up, which can deplete the
  carbon abundance and weaken C IV. In the low-activity giants,
  the λ1393 component of the Si IV doublet must be corrected
  for sharp absorptions, which we believe are caused by carbon
  monoxide in overlying cool material. <P />The normalized flux ratios
  (\Rscr≡f/f<SUB>bol</SUB>) of Si IV and X-rays among the ``coronal''
  yellow giants (lying just blueward of the ``noncoronal'' zone) fall on a
  uniform track, \Rscr<SUB>X</SUB>~\Rscr<SUP>2</SUP><SUB>SiIV</SUB>. In
  the noncoronal zone, however, the Si IV index is nearly constant
  (\Rscr<SUB>SiIV</SUB>~10<SUP>-8</SUP>), independent of \Rscr<SUB>X</SUB>
  (which ranges from ~10<SUP>-8</SUP> to &lt;~10<SUP>-10</SUP>). The
  mechanism that diminishes X-ray activity in the red giants is highly
  sensitive to an as yet unidentified stellar property. Photoelectric
  absorption by cool gas might play a more important role than previously
  suspected, particularly if hot magnetic loops are partly or completely
  buried in the chromosphere.

Title: Pondering Puzzling Profiles: MG II Emission from Carbon Stars
Authors: Carpenter, K. G.; Robinson, R. D.; Johnson, H. R.
Bibcode: 1997AAS...191.1306C
Altcode: 1997BAAS...29.1230C
  We have obtained spectroscopic observations of the Mg II h &amp; k
  emission lines from three carbon stars, using the moderate resolution
  (R&gt;=20,000) G270M grating of the Goddard High Resolution Spectrograph
  (GHRS) on the Hubble Space Telescope (HST). The emission profiles
  from all three stars are very broad and heavily mutilated by overlying
  absorption. The profiles from two of the stars, TX Psc (N0; C6,2) and
  TW Hor (N0; C7,2), are very similar. However, the profiles from the
  third star, UU Aur (N3; C5,3) are dramatically different from the other
  two stars on the blue side, with strong emission persisting out to ~
  -200 km/s (cf. to only weak emission out to ~ -100 km/s in TX Psc and
  TW Hor). If the intrinsic (i.e. chromospheric) width of the emission in
  the carbon stars is comparable to that in oxygen-rich giants, then the
  spectra of the first two carbon stars are easily understood in terms of
  additional overlying absorptions, but the amount of excess emission from
  the blue side of the UU Aur profiles is difficult to explain. If, on
  the other hand, the intrinsic width of the Mg II emission in the carbon
  stars is more comparable to that of the supergiant oxygen-rich stars
  (e.g. alpha Ori), then all the carbon stars have tremendous overlying
  absorption on both the blue and red wings of the profiles and UU Aur
  is notable only because it has significantly less absorption on the
  blue-side of the profiles, relative to the other carbon stars. In this
  paper, we present an analysis of the spectra and our interpretation,
  based on all the available data, of these fascinating and complex line
  profiles and their formation.

Title: Hubble Space Telescope Spectroscopy of the Carbon Star
    TX Piscium
Authors: Carpenter, Kenneth G.; Robinson, Richard D.; Johnson, Hollis
   R.; Eriksson, Kjell; Gustafsson, Bengt; Pijpers, Frank P.; Querci,
   Francois; Querci, Monique
Bibcode: 1997ApJ...486..457C
Altcode:
  Ultraviolet spectra obtained with the Hubble Space Telescope of the
  carbon star TX Piscium (HR 9004) are presented, along with analysis
  providing information on its outer atmosphere, including flow and
  turbulent velocities, line formation mechanisms, and variations with
  time. Both thermal (collisionally excited) and fluorescent emission
  from the chromosphere of the star appear to be formed near the stellar
  rest velocity, i.e., in a region below that in which the stellar wind is
  accelerated. Absorption self-reversals in the Mg II emission confirm the
  presence of an outflowing stellar wind at a mean velocity of about 9-10
  km s<SUP>-1</SUP>. Circumstellar absorption features (Mn I and Fe I)
  overlying the Mg II emission indicate a cool shell expanding at about
  5-6 km s<SUP>-1</SUP> relative to the photosphere. The widths (FWHM)
  of various emission lines indicate that the chromospheric turbulence is
  at least 16 km s<SUP>-1</SUP>, but that it may increase with altitude
  to as much as 34 km s<SUP>-1</SUP>. Three hours of integration on
  the C II] lines are examined for any signs of variability that might
  indicate the presence of shocks, but no statistically significant
  variations are seen. A previous identification (in spectra of UU Aur)
  of an emission line at 2807 Å, seen only in spectra of carbon stars,
  as belonging to Fe I multiplet UV45 pumped by the C II] line at 2325 Å
  is confirmed by the discovery of an absorption feature corresponding
  exactly to the wavelength of the pumped transition (Fe I UV13) near
  2325 Å. Lines from Fe II UV165, previously seen in solar off-limb
  spectra and in Goddard High-Resolution Spectrograph spectra of α Tau,
  are clearly present. The normally much stronger Fe II UV32, 62, and
  63 multiplets are seen but are weaker relative to both the UV165 lines
  and the intercombination lines of C II] and Si II] than in α Tau. The
  weakness of these Fe II lines is indicated both by their absolute flux
  levels and by their narrow, single-peaked profiles, which are in sharp
  contrast to the broad, double-peaked profiles seen in oxygen-rich cool
  giant and supergiant stars. The weakness of the Fe II lines and the
  presence of the Fe I 2807 Å line suggest that the ionization fraction
  of iron (Fe II/Fe I) is significantly lower in the outer atmospheres of
  carbon stars. Fluxes in emission lines of Fe II and Mg II are &gt;=2-3
  times lower than in a 1984 IUE spectrum of TX Psc, confirming that
  the latter was obtained at an epoch of unusual UV brightness for the
  star. The Mg II profiles are heavily mutilated by overlying absorption,
  even more so than in 1984. The TX Psc profiles are very similar to
  those seen in the carbon star TW Hor but are dramatically different
  than those in another carbon star, UU Aur, whose lines show violet
  wing emission out to much shorter wavelengths than in the other two
  stars. <P />Based on observations with the NASA/ESA Hubble Space
  Telescope, which is operated by the Association of Universities for
  Research in Astronomy, Inc., under NASA contract NAS 5-26555 and on
  observations at the Haute-Provence Observatory.

Title: The dynamical mass of the beat cepheid Y carinae and stellar
    opacities.
Authors: Bohm-Vitense, E.; Evans, N. R.; Carpenter, K.; Morgan, S.;
   Beck-Winchatz, B.; Robinson, R.
Bibcode: 1997AJ....114.1176B
Altcode:
  The beat Cepheid, Y Carinae A, has a B9 V companion, Y Car
  B. The primary period P<SUB>0</SUB> of the Cepheid is 3.64 days
  and the secondary, P<SUB>1</SUB>, is 2.56 days. Its period ratio
  P<SUB>1</SUB>/P<SUB>0</SUB> is thus 0.703. Y Car is the only beat
  Cepheid known to be a binary and thus offers us the unique opportunity
  to determine the dynamical mass for a beat Cepheid. We have determined
  its mass by measuring the orbital velocity amplitude of the hot
  companion Y Car B using the Goddard High-Resolution Spectrograph (GHRS)
  with the G200M grating on the Hubble Space Telescope. When combined
  with the ground-based orbital velocity amplitude of the Cepheid
  and the mass of the companion, the implied mass of the Cephieid
  is M=3.8±1.2M<SUB>sun</SUB>. With the Cepheid luminosity given
  by the period-luminosity relation, this mass, taken at face value,
  indicates excess mixing in the main sequence progenitor corresponding
  to convective overshoot by about 0.9 pressure scale height, however,
  the large error bars prevent a firm conclusion. As shown by Simon the
  period ratio for beat Cepheids depends sensitively on the opacities. For
  models calculated with Cox-Tabor opacities the period ratios for beat
  Cepheids indicate masses between one and two M<SUB>sun</SUB>. Models
  calculated with the new Livermore OPAL opacities on the other hand
  indicate masses around 4 solar masses. The good agreement of the beat
  mass with the dynamical mass, determined here for Y Car, provides a
  confirmation that the OPAL opacities are a significant improvement
  over the Cox-Tabor (1976) opacities.

Title: Observations of 3C273 with the Goddard High Resolution
    Spectrograph on the Hubble Space Telescope. II.
Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.;
   Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone,
   D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.;
   Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Snow, M.; Randall,
   C. E.; Tripp, T. M.; Ake, T. B.; Crenshaw, D. M.; Bruhweiler, F. C.
Bibcode: 1997AJ....114..554B
Altcode:
  Observations of the quasar 3C 273 taken with the Goddard High Resolution
  Spectrograph in November and December 1993 are presented here. We have
  included both the fully-reduced spectra, and spectra combined with
  our earlier (1991) observations. There are a total of 10 new medium
  resolution exposures covering four wavelength regions: 1164-1201
  Angstroms, 1214-1251 Angstroms, 1537-1573 Angstroms, and 1633-1670
  Angstroms. We confirm the suggestion of Morris et al. (1991) that the
  galactic Si IV lambda 1393 line is blended with an extragalactic lya
  line by observing the lyb counterpart to this extragalactic line. We
  obtain an improved upper limit on the C IV/H I ratio in these weak
  low redshift lya absorption systems by coadding the corresponding C IV
  spectral regions. Improved line profiles for the galactic C IV and N V
  absorption are also presented and discussed. The improved measurements
  lead to a downward revision of the galactic C IV column density, log N
  (C IV) = 14.46+/- 0.04.

Title: The Outer Atmospheres of Cool, Low Gravity Stars as Revealed
    by HST
Authors: Carpenter, Kenneth G.
Bibcode: 1997BaltA...6...73C
Altcode: 1997OAst....6...73C
  We have used the Goddard High Resolution Spectrograph (GHRS) on
  the Hubble Space Telescope (HST) to measure the macroturbulent and
  flow velocities, the acceleration of winds, and the amount of hot
  (transition-region) plasma in the outer atmospheres of Carbon and K - M
  Giant/Supergiant stars. We see the acceleration of the stellar winds in
  the chromospheres of several of these stars from initial velocities of 3
  - 9 km/s to upper velocities of 15 - 25 km/s and measured chromospheric
  macroturbulences ranging from approximately 25 to 35 km/s. We have
  found in the non-coronal giant alfa Tau weak C IV emission indicative
  of hot transition-region plasma, many new fluorescent lines of Fe II,
  and fluorescent molecular hydrogen emission and Ca II recombination
  lines seen for the first time in a giant star.

Title: The Mass of the Classical Cepheid V350 SGR
Authors: Evans, N. R.; Bohm-Vitense, E.; Carpenter, K.; Beck-Winchatz,
   B.; Robinson, R.
Bibcode: 1997PASP..109..789E
Altcode:
  Two medium resolution spectra of the hot companion of the Cepheid V350
  Sgr have been obtained with the Goddard High Resolution Spectrograph
  aboard the Hubble Space Telescope. Comparison of these spectra (in the
  wavelength range 1840 to 1880 \AA) with the spectrum of $\alpha$ Lyr
  shows that V350 Sgr B has a projected rotation velocity which may be as
  high as 150 km sec$^{-1}$. The velocity difference between the spectra
  of V350 Sgr B at two orbital phases is measured to be -23.1 $\pm$ 3.8
  km sec$^{-1}$. The error is dominated by the aperture centering. When
  combined with the orbital velocity variation of the Cepheid derived
  from the ground-based orbit and the mass of the companion deduced
  from IUE spectra, the mass of the Cepheid is found to be 5.2 $\pm$
  0.9 M$\sun$. The observed mass--luminosity combination of V350 Sgr A
  is a good match to recent evolutionary calculations which use moderate
  convective overshoot near the main sequence, however, the blue loops
  do not extend to temperatures as hot as the Cepheid. (SECTION: Stars)

Title: GHRS Observations of Cool Low-Gravity Stars. III. Plasma
    Flows and Turbulence in the Outer Atmosphere of α Orionis (M2 Iab)
Authors: Carpenter, Kenneth G.; Robinson, Richard D.
Bibcode: 1997ApJ...479..970C
Altcode:
  We present the results of a Goddard High Resolution Spectrograph (GHRS)
  study of flow and turbulent velocities in the outer atmosphere of the
  M2 Iab supergiant α Ori. Ions with observed chromospheric emission
  features include C I, C II, Si I, Si II, O I, Co II, Al II, Mg II,
  Cr II, Fe I, and Fe II, while the photospheric absorption spectrum
  is dominated by Fe I. The widths of optically thin lines of C II],
  Si II], Co II, and Fe II indicate an average chromospheric turbulent
  velocity (Doppler FWHM) in the range of 31-35 km s<SUP>-1</SUP>, which
  is substantially above the expected chromospheric sound velocity. The
  shape of the C II] profiles indicates that this turbulence is probably
  anisotropically distributed, with velocities preferentially directed
  along and/or perpendicular to the radial direction. The radial
  velocity of near-UV Fe I photospheric absorption lines averaged 18
  km s<SUP>-1</SUP>, somewhat smaller than the systemic RV of α Ori
  itself (21 km s<SUP>-1</SUP>) and significantly smaller than the RV
  of the optical Fe I lines (23 km s<SUP>-1</SUP>) at the time of the
  HST observations. The various components of the chromospheric emission
  lines had radial velocities in the range 7-36 km s<SUP>-1</SUP>. The
  emission wings for most of the ionic species averaged ~20 km
  s<SUP>-1</SUP>, i.e., they were nominally at rest with regard to
  the star. The central absorption features in these lines, however,
  showed lower velocities, averaging ~16 km s<SUP>-1</SUP>. The radial
  velocity of the central reversals in the stronger lines was also found
  to be correlated with the opacity of the lines, changing from ~20 km
  s<SUP>-1</SUP> for the lower opacity lines to ~14 km s<SUP>-1</SUP>
  for the higher opacity lines. This implies that we are directly viewing
  the acceleration of the stellar wind in the chromosphere from rest to
  about 7 km s<SUP>-1</SUP>. Contrary to the results reported earlier
  by Carpenter (1984) on the basis of IUE data, there is no indication
  of a deceleration of the wind at large distances from the star.

Title: The Mass of the Classical Cepheid S Muscae
Authors: Böhm-Vitense, Erika; Remage Evans, Nancy; Carpenter, Kenneth;
   Beck-Winchatz, Bernhard; Robinson, Richard
Bibcode: 1997ApJ...477..916B
Altcode:
  A good determination of the mass-luminosity relation for evolved stars
  on blue loops can determine the degree of excess mixing in the interiors
  of their main-sequence companions. In this study we determine the
  dynamical mass of the Cepheid binary S Muscae. This can be combined
  with its known luminosity and be fitted on evolutionary tracks to
  determine the amount of mixing in the main-sequence progenitor. <P
  />Using the Goddard High Resolution Spectrograph on the Hubble Space
  Telescope we have measured the orbital radial velocity changes for the
  companion of the Cepheid S Mus. Spectra taken at minimum and maximum
  orbital velocities were cross-correlated. The velocity difference was
  measured to be 30.6 +/- 0.4 km s<SUP>-1</SUP>. The difference for the
  orbital velocities of the Cepheid for the same phases was determined
  to be 26.9 km s<SUP>-1</SUP> +/- 0.4 km s<SUP>-1</SUP>. This gives
  a velocity ratio of 1.14 +/- 0.02, which gives us the mass ratio for
  the companions. Adding possible centering errors of the target in the
  entrance apertures the error limit would be increased to +/-0.06. <P
  />The derived spectral types of the companion S Mus B range from B3
  V to B5 V depending on the criterion used to determine it, with an
  average spectral type B3.8 V. Using the average spectral type and the
  main-sequence mass-spectral type relation from Andersen &amp; Harmanec
  we find for S Mus B a mass of 5.2 +/- 0.2 M<SUB>⊙</SUB>. With the
  newly determined mass ratio the mass for the Cepheid S Mus A comes out
  to be 5.9<SUP>+0.7</SUP><SUB>-0.6</SUB> M<SUB>⊙</SUB>. <P />Taking
  the mass of 5.9 M<SUB>⊙</SUB> at face value and adopting the absolute
  visual magnitude of M<SUB>v</SUB> = -4.29 (log L/L<SUB>⊙</SUB> =
  3.62) for the Cepheid S Mus this indicates mixing in its main-sequence
  progenitor slightly in excess of the one assumed for the Maeder and
  Meynet evolutionary tracks. The present uncertainties in mass and
  luminosity prevent, however, a firm conclusion about the exact degree
  of mixing. <P />Based on observations made with the NASA/ESA Hubble
  Space Telescope, obtained at the Space Telescope Science Institute,
  which is operated by the Association of Universities for Research in
  Astronomy, Inc., under NASA Contract No. NASS-26555.

Title: Winds and Mass-Loss from Evolved, Low-Gravity Cool Stars
Authors: Carpenter, K.; Robinson, R.
Bibcode: 1997IAUJD...8E..28C
Altcode:
  The character of the winds and the amount of mass-loss from stars
  during the red giant and supergiant stage of evolution are critical
  to the progression of that evolution. We therefore summarize here the
  results of a series of programs utilizing the Goddard High Resolution
  Spectrograph (GHRS) on the Hubble Space Telescope (HST) to study the
  winds and mass-loss from the surface of evolved, low-gravity cool
  stars. We discuss the structure of the chromospheres in which the
  base of these stellar winds lie, the velocity of the wind and its
  acceleration with height, and what these spectra tell us about the
  mass-loss from these stars. Because of its relevance to this Joint
  Discussion, we will also discuss in some detail what we have learned
  about real-time variability of these phenomena and the implied somewhat
  erratic nature of the mass-loss process in at least some of these stars.

Title: Fishing in the Coronal Graveyard
Authors: Ayres, T. R.; Brown, A.; Harper, G. M.; Bennett, P. D.;
   Linsky, J. L.; Carpenter, K. G.; Robinson, R. D.
Bibcode: 1996AAS...189.7815A
Altcode: 1996BAAS...28.1379A
  Hot coronae (T ~ 10(6) K) are thought to be rare among single giant
  stars to the right of the ``Linsky--Haisch dividing line'' near K0 in
  the H--R diagram. K and M giants are such slow rotators that absence of
  dynamo generated magnetic activity would be natural. Nevertheless,
  gamma Dra (K5 III) unexpectedly was detected in FUV coronal
  proxies---hot lines Si IV lambda 1393 and C IV lambda 1548---by HST
  /GHRS during Science Verification, and subsequently was discovered
  as a faint X-ray source in a deep ROSAT /PSPC pointing. Is gamma Dra
  anomalous, or is the lack of coronal detections among the K giants
  simply a matter of insufficient sensitivity? We have used the GHRS
  low resolution mode to search for additional examples of hot lines
  among inactive single red giants. Si IV provides a clean diagnostic
  of subcoronal material because it falls near the peak sensitivity
  of the G140L mode and does not suffer from abundance depletions that
  can affect C IV in red giants. X-ray/Si IV ratios are such that HST
  can reach to much fainter limiting ``coronal'' magnitudes than even
  very deep ROSAT pointings. In every target so far examined, we find
  weak---but statistically significant---Si IV emission. These include:
  the ancient red giant Arcturus (alpha Boo: K1 III), recorded at the
  end of Cycle 5; and epsilon Crv (K2.5 III) and epsilon Sco (K2 III)
  observed in Cycle 6. X-ray/Si IV ratios of red giants (for which
  measurements, or upper limits, of both diagnostics are available)
  fall on a uniform track, extending downward from active K0 ``Clump''
  giants like beta Ceti all the way to Arcturus itself, in the depths of
  the ``coronal graveyard.'' The systematic behavior argues that magnetic
  dynamo action continues even when long term angular momentum loss has
  slowed the stellar spin to a crawl. This work was supported by grant
  GO-06066.01-94A from STScI.

Title: New Results on Cepheid Masses
Authors: Evans, N. R.; Bohm-Vitense, E.; Carpenter, K.; Robinson,
   R.; Beck-Winchatz, B.
Bibcode: 1996AAS...189.9608E
Altcode: 1996BAAS...28.1399E
  Masses for Cepheid variable stars can be measured by combining the
  orbital velocity amplitude for the Cepheid (from a ground-based orbit)
  with the orbital velocity amplitude of a hot main sequence companion
  (observed in the ultraviolet from satellites such as IUE and HST) and
  the mass of the companion (inferred from from the ultraviolet energy
  distribution). Observations of 5 binary systems are now completed
  or in progress with the Goddard High Resolution Spectrograph on the
  Hubble Space Telescope. Recently completed observations of U Aql lead
  to a mass of 5.1 +/- 1.1 Msun . We will discuss the results for S Mus,
  V350 Sgr, U Aql, and Y Car, and the constraints they place on stellar
  evolution calculations. As would be expected, some of the B companions
  have high rotational velocities, decreasing the accuracy with which
  their orbital velocities can be measured. The preliminary conclusion
  from the 4 HST targets and SU Cyg (mass from IUE observations) is that
  a weighted mean indicates no convective overshoot but the mode (which
  reflects the HST results better) agrees with the modest overshoot
  used in the Geneva evolutionary calculations. Financial Support was
  provided by a NASA grant GO-4541-01 to EB--V and GO-4541.02 to KGC,
  a grant from the Natural Sciences and Engineering Council, Canada to
  NRE, from the AXAF Science Center NASA Contract NAS8-39073.

Title: Observing Stellar Coronae with the Goddard High Resolution
    Spectrograph. II. The RS CVn Binary System HR 1099
Authors: Robinson, R. D.; Airapetian, V. S.; Maran, S. P.; Carpenter,
   K. G.
Bibcode: 1996ApJ...469..872R
Altcode:
  We report time series observations of the RS CVn star HR 1099 taken
  with the Goddard High Resolution Spectrograph onboard the Hubble Space
  Telescope. The data cover a wavelength range from 1342 to 1375 Å and
  show a measurable continuum, as well as emission lines of O I, C I,
  CII, Fe II, O V, and Fe XXI. The chromospheric and transition region
  features are seen only in the active K1 IV component of the binary
  system, while the Fe XXI (1O<SUP>7</SUP> K) flux may come from both
  components, with the active component having the stronger flux. There is
  no indication of Fe MI emission, formed at 1.3 x 10<SUP>6</SUP> K. The
  width of the Fe XXI profile indicates that the corona of the primary
  is unlikely to extend to heights greater than 2.3R<SUB>⋆</SUB>,
  while other indicators suggest that the average loops are really
  much smaller, having a length of ∼3 x 10<SUP>10</SUP> cm with an
  electron density on the order of 10<SUP>10</SUP> cm<SUP>-3</SUP>. Some
  evidence for atmospheric turbulence is detected in all of the observed
  emission lines. This turbulence initially increases with height, going
  from less than 30 km s<SUP>-1</SUP> in the chromosphere to as much
  as 150 km s<SUP>-1</SUP> in the transition region. The turbulence
  then decreases in the corona, where velocities of less than 65 km
  s<SUP>-1</SUP> are indicated. Theoretical fits to the O V profile
  also suggest that this turbulence is anisotropically distributed,
  with motions directed primarily along or perpendicular to the radial
  direction. While admitting the possibility that the atmosphere is
  heated by microflare events, we examine an alternative heating process
  that involves the damping of MHD turbulence, which might be generated
  by nonlinear Alfvén waves or by shocks. Simple calculations indicate
  that the observed turbulence is sufficient to account for the transition
  region and coronal heating.

Title: UV Emission from the Atmosphere of Jupiter After the S-Impact
    of Comet SL9
Authors: Carpenter, K. G.; McGrath, M. A.; Yelle, R. V.
Bibcode: 1996DPS....28.2247C
Altcode: 1996BAAS...28.1150C
  The Hubble Space Telescope Faint Object Spectrograph was used to
  obtain a UV spectrum of the impact site of the S-fragment of comet
  SL9 approximately 45 minutes after the entry of the fragment into the
  atmosphere of Jupiter. This spectrum contains ultraviolet emission
  lines of neutral and ionized metals, including Mg I, Mg II, Fe I,
  Fe II, and Si I. Initial analyses of these data were presented by
  Noll et al. (1995, Science, 267, 1307) based on a pure solar resonance
  fluoresence synthetic spectrum and assuming collisional excitation at
  1000 K, and by Carpenter et al. (DPS, Oct. 1995) who added non-resonance
  fluorescence and examined the possibility that some of the emission was
  caused by thermal excitation of metastable levels during the fireball
  and splashback phases of the impact. Since these line formation models
  do not fully account for the observed relative and absolute line fluxes,
  we have enhanced our model to include non-LTE effects, heating of the
  atmosphere due to infalling gas and dust, and the effects of multiple
  scatterings of photons as they attempt to exit the atmosphere of
  Jupiter at frequencies within optically thick lines. We compare the
  synthetic spectrum produced with this model to the observed spectrum
  and discuss the physical conditions and elemental abundances inferred
  from this comparison.

Title: High Signal-to-Noise Ratio Observations of Weak Interstellar
    Absorption Lines Towards XI Ophiuchi With the Goddard High-Resolution
    Spectrograph Aboard the Hubble Space Telescope
Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.;
   Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone,
   D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.;
   Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Hogen, R.; Snow, M.;
   Cardelli, J. A.; Ake, T. B.; Bruhweiler, F.
Bibcode: 1996AJ....112.1128B
Altcode:
  We present an atlas and tabulation of weak interstellar absorption lines
  in the ultraviolet spectrum of ζ Ophiuchi in four selected wavelength
  regions observed with the Goddard High Resolution Spectrograph aboard
  the Hubble Space Telescope. The signal-to-noise ratio ranges from 150 to
  nearly 400, and the spectral resolving power exceeds 20 000, allowing
  2σ detections of features as weak as Wλ=0.8 mÅ. We report positive
  measurements of two lines of OH, and weak detections of P I, Tl II,
  and N V. Upper limits of Wλ&lt;1 mÅ are found for the molecules
  H<SUB>2</SUB>O, HCl, SiO, NO+, and CH<SUB>2</SUB>. Similar limits
  are found for heavy elements Te II, Co II, and Sb II. Three lines are
  present in our spectrum for which we have no identifications. They are
  found at wavelengths of λ=1229.84, 1313.98, and 1314.23 Å. However,
  none of the features reported by previous authors as unidentified
  absorption lines in the wavelength regions we have observed are present
  in our data.

Title: Hubble Space Telescope Observations of the Seyfert Galaxy
NGC 3783: Discovery of Variable C IV Absorption
Authors: Maran, Stephen P.; Crenshaw, D. Michael; Mushotzky, Richard
   F.; Reichert, Gail A.; Carpenter, Kenneth G.; Smith, Andrew M.;
   Hutchings, John B.; Weymann, Ray J.
Bibcode: 1996ApJ...465..733M
Altcode:
  We have discovered variable absorption lines in HST spectra of the
  Seyfert 1 galaxy NGC 3783. C IV λλ1548.2, 1550.8 absorption is present
  in an FOS spectrum on 1992 July 27 and a GHRS spectrum on 1994 January
  16 at a radial velocity of -450 km s^-1^ relative to the emission-line
  peak, but there is no evidence for absorption in a GHRS spectrum on 1993
  February 5. A GHRS spectrum on 1993 February 21, obtained just 16 days
  after the spectrum with no detectable C IV absorption, shows strong
  N V λλ1238.8, 1242.8 absorption lines, also at a radial velocity of
  -450 km s^-1^. The observations place constraints on the two types of
  models for absorption-line variability: bulk motion into the line of
  sight, and variable ionization of gas already in the line of sight.

Title: Probing the Chromospheric Structure of Alpha Tau
Authors: Carpenter, Kenneth
Bibcode: 1996hst..prop.6722C
Altcode: 1996hst..prop.3133C
  Fluorescent H_2 lines {excited by Hydrogen LyAlpha} and Ca II lines
  formed by recombination after photoionization by H LyAlpha were recently
  seen in GHRS spectra of the K5 III star Alpha Tau. This is the first
  time these lines have been seen in a giant star. The presence of these
  lines provides an opportunity to probe the structure of the upper
  chromosphere {Ca II} and of the low chromosphere/temperature minimum
  region {H_2} in this star and to test existing and new theoretical
  models of the outer atmosphere of Alpha Tau. In addition, the H_2 lines
  allow us to probe cooler regions than possible using the standard atomic
  emission line diagnostics and thus enable us to test the hypothesis of
  Wiedemann et al. {1994 ApJ 423, 806} that the atmosphere of cool giants
  are thermally bifurcated in the region above the photosphere. We propose
  to obtain, during Cycle 6, observations of the full set of Ca II and
  H_2 lines needed to perform these analysis and tests and to use these
  data to create new models of the chromosphere of Alpha Tau.

Title: HST Studies of Carbon and K-M Giant/Supergiant Stars
Authors: Carpenter, K. G.; Robinson, R. D.
Bibcode: 1996swhs.conf..418C
Altcode:
  No abstract at ADS

Title: Empirical constraints on wind flows and turbulence from HST
    observations of cool giants and supergiants
Authors: Carpenter, K. G.
Bibcode: 1996ASPC..109..243C
Altcode: 1996csss....9..243C
  No abstract at ADS

Title: Rapid UV spectroscopy of flares on YZ CMi
Authors: Robinson, R. D.; Woodgate, B. E.; Carpenter, K. G.
Bibcode: 1996ASPC..109..285R
Altcode: 1996csss....9..285R
  No abstract at ADS

Title: Identification and analysis of UV emission lines observed near
    1550 Angstroms in the spectrum of alpha Tau obtained with the GHRS
Authors: McMurry, A. D.; Jordan, C.; Rowe, A. K.; Carpenter, K. G.;
   Robinson, R. D.
Bibcode: 1996ASPC..109..271M
Altcode: 1996csss....9..271M
  No abstract at ADS

Title: Examining the coronal heating on the RS CVn binary HR 1099
Authors: Airapetian, V.; Robinson, R. D.; Maran, S. P.; Carpenter,
   K. G.
Bibcode: 1996ASPC..109..249A
Altcode: 1996csss....9..249A
  No abstract at ADS

Title: The Transition Region, Corona, Chromosphere, and Wind of the
    K5 Giant gamma Draconis
Authors: Brown, A.; Carpenter, K. G.; Robinson, R. D.; Harper, G. M.;
   Deeney, B. D.; Ayres, T. R.
Bibcode: 1995AAS...18710303B
Altcode: 1995BAAS...27.1430B
  Gamma Draconis (K5 III) is the first single, normal late K giant
  located on the red side of the coronal ``dividing line'' known to
  show conclusive evidence for both hot ( ~ 10(5) K) transition \
  region (TR) and coronal (&gt; 10(6) K) plasma. We present HST GHRS
  ultraviolet spectra of gamma Dra obtained on 1995 July 20 and 1991
  April 6/18. These observations include spectra obtained at low, medium,
  and echelle resolution that provide a full set of chromospheric and
  TR emission line fluxes and profiles. These are combined with ROSAT
  PSPC observations to measure the TR and coronal properties, such
  as emission measure distribution, electron density, and nonthermal
  velocity fields, of this star. The high temperature emissions of gamma
  Dra are compared to those of a sample of hybrid-chromosphere bright
  giants and supergiants. This work is supported by Space Telescope
  Science Institute grant GO-06068.01-94A and NASA grants NAG5-1792 and
  NAGW-4529 to the University of Colorado.

Title: The Mass of the Cepheid S Muscae.
Authors: Bohm-Vitense, E.; Evans, N. R.; Beck-Winchatz, B.; Carpenter,
   K.; Robinson, R.
Bibcode: 1995AAS...18710205B
Altcode: 1995BAAS...27.1428B
  Using the Goddard High Resolution Spectrograph on the Hubble Space
  Telescope we have measured the orbital radial velocity changes for
  the companion of the Cepheid S Muscae. The observations were done
  at minimum and maximum orbital velocities. The two spectra were
  cross-correlated. The velocity difference was measured to be 30.6 +/-
  0.4 km/s. The difference for the orbital velocities of the Cepheid
  for the same phases was determined to be 26.9 +/-0.4 km/s. This gives
  a mass ratio of 1.14 +/-0.06. For a spectral type between B3.5 V and
  B5 V for the companion S Mus B its mass is 5.0 +/- 0.3 M(sun). With
  the mass ratio of 1.14 the mass of the Cepheid, with a period of 9.6
  days, comes out to be 5.7 +/- 0.4 solar masses. This compares with a
  pulsational mass of 5.5 solar masses. Taking the 5.7 solar masses for
  the Cepheid at face value its absolute visual magnitude of M(V)=-4.29
  indicates a high degree of excess interior mixing in its main sequence
  progenitor corresponding to convective overshoot by one pressure
  scale height. Even for the upper mass limit the excess mixing has to
  correspond to convective overshoot by 1/2 pressure scale height.

Title: The Astrophysical Laboratory RR Tel: Observations
Authors: Harper, G. M.; Brown, A.; Robinson, R. D.; Jordan, C.;
   Carpenter, K. G.; Shore, S. N.
Bibcode: 1995AAS...187.1910H
Altcode: 1995BAAS...27.1313H
  The rich emission line spectrum of the bright symbiotic nova RR
  Tel provides one of the best laboratories for determining empirical
  values of atomic parameters, including branching ratios, Einstein
  A-values and electron collision strengths. In addition to providing
  atomic parameters not measurable in the laboratory, the observations
  also test recent theoretical calculations of these parameters. In July
  1995 we obtained high quality low and medium resolution, large aperture
  spectra of RR Tel using the Goddard High Resolution Spectrograph (GHRS)
  on board the Hubble Space Telescope. These spectra sample wavelengths
  from 1100 Angstroms to 2680 Angstroms and contain numerous lines of
  astrophysical interest which will be used to derive empirical atomic
  data (e.g. branching ratios in C II], N III], O III] and O IV])
  as well as lines from which the local temperature and density can
  be determined. The GHRS spectra have greater dynamic range and lower
  background noise than available high resolution IUE data, permitting
  detailed evaluation of spectral diagnostics even for the weak emission
  features from some intercombination and forbidden transitions. In this
  paper we show examples of the spectra, discuss the atomic transitions
  for which atomic data will be derived and describe the methods used in
  determining these parameters. RR Tel and AG Peg, both of which have been
  observed with the GHRS, are fundamental for studying time variability
  of spectra of a symbiotic nova and the GHRS observations will be
  compared with previous IUE results to investigate this variability. We
  will also discuss the observed flows and turbulence found from the
  line profiles as well as the shape of the UV continuum. Support for
  this work was provided by NASA through grant number GO-05863.01-94A
  from the Space Telescope Science Institute, which is operated by the
  Association of Universities for research in Astronomy, Inc., under
  NASA contract NAS5-26555.

Title: A Search for Microflaring Activity on dMe Flare
    Stars. I. Observations of the dM8e Star CN Leonis
Authors: Robinson, R. D.; Carpenter, K. G.; Percival, J. W.;
   Bookbinder, J. A.
Bibcode: 1995ApJ...451..795R
Altcode:
  Microflares are frequent, short-duration, energetically weak
  disturbances occurring in the nonradiatively heated regions of the
  Sun and other magnetically active stars. They are thought to be the
  low-energy extension of flares commonly seen on active dMe stars and
  may be a major source of heating the chromosphere and corona of cool
  stars in general. In this paper we describe rapid time sequence UV
  photometry of the dMe star CN Leo taken with the High Speed Photometer
  (HSP) aboard the Hubble Space Telescope (HST). The filter was centered
  at 240 nm, near wavelengths at which flares are expected to have
  maximum intensity and the stellar background is small. During 2 hr of
  on-source observing, a total of 32 flarelike events were detected,
  with integrated counts ranging from 12 to more than 14,000. In most
  cases the events had integrated energy ranging between 10<SUP>27</SUP>
  and 10<SUP>28</SUP> ergs and can be classified as microflares. A
  considerable fine structure was seen in these events, with substantial
  variations sometimes occurring on timescales of less than 1 s. The
  occurrence rates for the smaller events showed a power-law distribution,
  with a slope comparable to that seen for larger events observed from
  the ground. Extrapolating the occurrence rate relation to nanoflare
  energies indicates a predicted count rate that is significantly smaller
  than that observed, suggesting that the nanoflares have a different
  energy distribution than the larger events.

Title: The Goddard High Resolution Spectrograph: In-Orbit Performance
Authors: Heap, S. R.; Brandt, J. C.; Randall, C. E.; Carpenter, K. G.;
   Leckrone, D. S.; Maran, S. P.; Smith, A. M.; Beaver, E. A.; Boggess,
   A.; Ebbets, D. C.; Garner, H. W.; Hutchings, J. B.; Jura, M.; Linsky,
   J. L.; Savage, B. D.; Cardelli, J. A.; Trafton, L. M.; Walter, F. M.;
   Weymann, R. J.; Ake, T. B.; Crenshaw, D. M.; Malumuth, E. M.; Robinson,
   R. D.; Sandoval, J. L.; Shore, S. N.; Wahlgren, G. M.; Bruhweiler,
   F.; Lindler, D. J.; Gilliland, R. L.; Hulbert, S. J.; Soderblom, D. R.
Bibcode: 1995PASP..107..871H
Altcode:
  The in-orbit performance of the Goddard High Resolution Spectrograph
  onboard the Hubble Space Telescope (HST) is presented. This report
  covers the pre-COSTAR period, when instrument performance was
  limited by the effects of spherical aberration of the telescope's
  primary mirror. The digicon detectors provide a linear response
  to count rates spanning over six orders of magnitude, ranging from
  the normal background flux of 0.01 counts diode ^-1 s^-1 to values
  larger than 10^4 counts diode^-1 s^-1. Scattered light from the
  first-order gratings is small and can be removed by standard background
  subtraction techniques. Scattered light in the echelle mode is more
  complex in origin, but it also can be accurately removed. Data
  have been obtained over a wavelength range from below 1100 A to
  3300 A, at spectral resolutions as high as R = lambda/delta-lambda =
  90,000. The wavelength scale is influenced by spectrograph temperature,
  outgassing of the optical bench, and interaction of the magnetic field
  within the detector with the earth's magnetic field. Models of these
  effects lead to a default wavelength scale with an accuracy better
  than 1 diode, corresponding to 3 km s^-1 in the echelle mode. With
  care, the wavelength scale can be determined to an accuracy of 0.2
  diodes. Calibration of the instrument sensitivity functions is tied into
  the HST flux calibration through observations of spectrophotometric
  standard stars. The measurements of vignetting and the echelle
  blaze function provide relative photometric precision to about 5% or
  better. The effects of fixed-pattern noise have been investigated,
  and techniques have been devised for recognizing and removing it
  from the data. The ultimate signal-to-noise ratio achievable with the
  spectrograph is essentially limited only by counting statistics, and
  values approaching 1000:1 have been obtained. (SECTION: Astronomical
  Instrumentation)

Title: Formation of Atomic Emission Lines in the Atmosphere of
    Jupiter After the Comet Shoemaker-Levy 9 S Impact
Authors: Carpenter, K. G.; McGrath, M. A.; Yelle, R. V.; Noll, K. S.;
   Weaver, H. A.
Bibcode: 1995DPS....27.2203C
Altcode: 1995BAAS...27Q1118C
  No abstract at ADS

Title: An Atlas of Alpha Orionis Obtained with the Goddard High
    Resolution Spectrograph on the Hubble Space Telescope
Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess,
   A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.;
   Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith,
   A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R.; Snow, M.; Randall,
   C. E.; Ake, T. B.; Robinson, R. D.; Wahlgren, G.
Bibcode: 1995AJ....109.2706B
Altcode:
  An atlas of observations of the late-type supergiant a Orionis taken
  with the Goddard High Resolution Spectrograph in 1992 September is
  presented. We have included identifications of the major features along
  with the fully reduced spectrum. The 33 exposures consist of 3 high
  resolution (R∼80,000) and 30 medium resolution (R ∼20,000∼35,000)
  observations. The latter provide complete wavelength coverage from
  1980 to 3300 Å.

Title: GHRS Observations of Cool, Low-Gravity Stars. II. Flow
    and Turbulent Velocities in the Outer Atmosphere of gamma Crucis
    (M3.4 III)
Authors: Carpenter, Kenneth G.; Robinson, Richard D.; Judge, Philip G.
Bibcode: 1995ApJ...444..424C
Altcode:
  The Goddard High Resoulution Spectrograph (GHRS) on the Hubble Space
  Telescope (HST) has been used to obtain medium (R = 20,000) and high
  (R = 85,000) resoultion UV spectra of chromosphere emission features
  for the M3.4 III star gamma Cru. Small Science Aperture (SSA) G270M and
  Echelle-B spectra of selected regions in the 2300-2850 A range were
  obtained to determine the kinematics of the chromosphere using lines
  of C2), Fe2, Co2, Si1/2), Ni2, Mn2, and Mg2. Profiles of C2) (UV 0.01)
  lines and fluorescently excited lines of low optical depth indicate
  average turbulent velocities (Doppler FWHM) of 30.2 +/- 1.3 and 28.8 +/-
  1.3 km/s, respectively. The fluorescent emission lines (mean RV = 21.3
  +/- 0.9 km/s) and the wings of the emission components of Fe2 lines
  (mean RV = 22.8 +/- 0.4 km/s) are approximately at rest relative to
  the radial velocity of the star (21 km/s), while the C2) lines show
  a modest inflow (mean RV = 23.1 +/- 0.9 km/s). The more opaque lines
  of Fe2 and Mg2 exhibit complex profiles resulting from line formation
  in an optically thick, extended expanding atmosphere. The emission
  wings of these lines are broadened by multiple scattering, and they are
  centered near the photospheric radial velocity. Closer to line center,
  these strong lines show a strong blueshifted self-absorption feature
  (already seen in IUE data), indicative of formation in an expanding
  chromosphere, and a previously unseen dip in the profiles on the red
  side of line center. The absorption components, when extracted using
  simple Gaussian fits, show strong correlations with the relative
  optical depths of the lines. The derived absorption flow velocities
  converge to the photospheric velocity as one examines spectra features
  formed deeper in the atmosphere. The blueward abosrption velocity
  increases in magnitude from about 7 to 14 km/s with increasing line
  optical depth - the strong absorptions directly map the acceleration
  of the outflowing stellar wind, while the interpretation of the
  weaker redshifted absorptions is more ambiguous, indicating either an
  inflow of material or formation in an extended, spherically expanding
  outflow. The Mg2 and Fe2 profiles, taken together, imply that the wind
  speed decreases between the atmospheric layers where the Mg2 and Fe2
  self-absorption components are formed. Interstellar absorptions are seen
  in the resonance lines of Mg2 (UV 1) and Fe2 (UV1) with zero-volt lower
  levels, at about -3 km/s, consistent with models of the interstellar
  medium in the direction of gamma Cru. Finally, we have detected the Mg2
  'satellite lines' seen in solar spectra obtained above the limb. In
  gamma Cru these lines are probably fluorescently excited by H Ly beta.

Title: Outer Layers of a Carbon Star: The View from the Hubble
    Space Telescope
Authors: Johnson, Hollis R.; Ensman, Lisa M.; Alexander, David R.;
   Avrett, Eugene H.; Brown, Alexander; Carpenter, Kenneth G.; Eriksson,
   Kjell; Gustafsson, Bengt; Jorgensen, Uffe G.; Judge, Philip D.; Linsky,
   Jeffrey L.; Luttermoser, Donald G.; Querci, Francois; Querci, Monique;
   Robinson, Richard D.; Wing, Robert F.
Bibcode: 1995ApJ...443..281J
Altcode:
  To advance our understanding of the relationship between stellar
  chromospheres and mass loss, which is a common property of carbon stars
  and other asymptotic giant branch stars, we have obtained ultraviolet
  spectra of the nearby N-type carbon star UU Aur using the Hubble
  Space Telescope (HST). In this paper we describe the HST observations,
  identify spectral features in both absorption and emission, and attempt
  to infer the velocity field in the chromosphere, upper troposphere,
  and circumstellar envelope from spectral line shifts. A mechanism
  for producing fluoresced emission to explain a previously unobserved
  emission line is proposed. Some related ground-based observations are
  also described.

Title: MG II H and K Profiles in High-Luminosity, Late-Type Stars
Authors: Robinson, R. D.; Carpenter, K. G.
Bibcode: 1995ApJ...442..328R
Altcode:
  Using high-resolution spectroscopic data taken with the Goddard High
  Resolution Spectrographic (GHRS) aboard the Hubble Space Telescope
  (HST) and with the International Ultraviolet Explorer (IUE) satellite,
  we compare the profiles of the Mg II h and k lines seen in stars with
  spectral types ranging from early K through mid-M and luminosities
  from giants to supergiants. For all of these stars the lines are
  broad emission features with a central absorption. When plotted on a
  velocity scale the absorption features of the h and k lines agree very
  well in both shape and position, as do the blue wings of the emission
  component. The red wings of the emission, however, show a pronounced
  difference, with the k line wing consistently shifted to the red of the
  h line wing. At present the reason for this discrepancy is unknown,
  but we suggest several possibilities, including radiative transfer
  effects and high-speed stellar winds.

Title: Fe II Line Profiles as Stellar Wind Diagnostics in M Giant
    and Supergiant Stars
Authors: Carpenter, K. G.; Robinson, R. D.
Bibcode: 1995AAS...186.2220C
Altcode: 1995BAAS...27..844C
  Detailed study of high resolution, high signal-to-noise chromospheric
  Fe II emission line profiles, obtained with the Goddard High Resolution
  Spectrograph on the Hubble Space Telescope, provides an opportunity
  to probe the flow velocities in the outer atmospheres/winds of cool,
  low-gravity stars. We have previously reported seeing the acceleration
  of the outflowing wind in such data from several M-giant stars,
  including gamma Cru (M3.4 III), mu Gem (M3 IIIab), and alpha Tau (K5
  III). Early attempts to do the same with the M-supergiant alpha Ori
  (M2 Iab) met with limited success, due to the high-opacity of its outer
  atmosphere and the significant differences in the character and behavior
  of the observed line profiles in the supergiant spectrum. Further
  analysis of the GHRS observations of Fe II lines in alpha Ori has
  now enabled us to detect the accelerating outflow in it's wind as
  well. A detailed comparison of the observed Fe II profiles and the
  flows inferred from those profiles, with those for the less-luminous,
  but similar T<SUB>eff</SUB> M-giant gamma Cru are presented.

Title: Line Identifications in Goddard High Resolution Spectrograph
    Observations of Cool, High-Luminosity Stars
Authors: Carpenter, K. G.; Robinson, R. D.
Bibcode: 1995ASPC...81..559C
Altcode: 1995lahr.conf..559C
  No abstract at ADS

Title: Observations of Fe XXI on the RS CVn star HR 1099: deducing
    the coronal properties
Authors: Robinson, R. D.; Airapetian, V. S.; Maran, S. P.; Carpenter,
   K. G.
Bibcode: 1995IAUS..176P.191R
Altcode:
  No abstract at ADS

Title: GHRS Spectra of alpha Tau
Authors: Carpenter, K.; Robinson, R.; Judge, P.
Bibcode: 1994AAS...185.4509C
Altcode: 1994BAAS...26.1380C
  Goddard High Resolution Spectrograph (GHRS) observations of the K5 giant
  alpha Tau were obtained on 8 April 1994. Spectra of approximately 40
  Angstroms-wide regions centered near 1300, 1550, 1660, 1995, 2340, 2760,
  and 2800 Angstroms were obtained through the Small Science Aperture
  (SSA) with medium resolution (R=20,000) gratings. These data provide
  high-precision profiles of a variety of lines formed in the stellar
  chromosphere and transition region, including O I, Fe II, C I, C II],
  Si II], Mg II, and C IV. Self-reversed emission from O I, Fe II,
  and Mg II provide information on the wind flow velocities, with all
  three ions showing both red and blue-shifted absorption components,
  as seen previously in the Fe II emission from the later-type giants
  gamma Cru and mu Gem. The first evidence for hot plasma in the outer
  atmosphere of alpha Tau is seen in the G160M spectrum centered near
  1550 Angstroms@. This spectrum shows very broad, but distinct features
  due to the C IV (UV 1) doublet, as well as a myriad of much narrower
  emissions formed at cooler temperatures, such as (fluorescent) Fe II and
  perhaps Ni II and C I. C I (UV 2) is seen in emission and a comparison
  of its flux with that in C I (UV 32) will allow an estimation of the C
  I chromospheric column density. Multiple observations of the C II] (UV
  0.01) intercombination multiplet were obtained to search for evidence
  of shocks and/or propagating waves. Results of that search will be
  presented. Finally, very high-resolution (R=85,000) echelle spectra
  were obtained of the Mg II resonance doublet near 2800 Angstroms@. These
  emission features show strong interstellar, stellar, and circumstellar
  absorption components at, above, and below the stellar rest velocity.

Title: GHRS and IUE Observations of the Symbiotic Binary CI Cygni
Authors: Jalakas, M.; Stencel, R. E.; Carpenter, K. G.; Robinson, R. D.
Bibcode: 1994AAS...185.2111J
Altcode: 1994BAAS...26.1345J
  The interacting symbiotic binary star, CI Cygni, is a system
  which consists of a hot star orbiting a red giant. Matter from
  the larger star is being transfered to the smaller one. Both IUE
  and more recently, the Goddard High Resolution Spectrograph on HST
  have detected variable ultraviolet emission lines produced by this
  transfer. Phase-dependent changes to the doppler velocity of the
  matter allow us to map the direction of the flow. Using the HST
  snd IUE spectrometers, we re-examined two different types of lines
  (resonance and intercombination) which had been reported to show
  velocity differences. We will present an analysis of these data showing
  the relative locations of high and low density features in the matter
  transfer in this system. The lead authors are pleased to acknowledge
  partial support for this effort through NASA grant NAG5-2368 to the
  University of Denver.

Title: Coronal Heating Mechanisms: A Search for Microflare Activity
    on YZ CMi
Authors: Robinson, R. D.; Carpenter, K. G.; Percival, J. W.
Bibcode: 1994AAS...185.4506R
Altcode: 1994BAAS...26.1380R
  We report on time series photometric observations of the dM4.5e flare
  star YZ CMi taken in 1993 Nov with the High Speed Photometer aboard
  the Hubble Space Telescope. The data consist of five 30 minute time
  sequences, with a sampling rate of 0.01s, which were taken through
  the F240W filter (centered at 240nm with a 800 Angstroms width). This
  setup was selected since the flare energy is expected to be large and
  the stellar background is small at these wavelengths. The observations
  show a stellar background of 120 counts s(-1) on which are superimposed
  well defined flare events ranging in integrated energy from 10(28)
  to 10(30) ergs, as well as longer term variations with an amplitude
  of up to 50% of the continuum intensity and time scales ranging from
  several minutes to hours. These results are compared with data from
  the dM8e flare star CN Leo, obtained earlier with the same experimental
  setup. CN Leo has a quiescent X-ray flux which is 1/30 that of YZ CMi,
  but had a higher occurrence rate of microflares. On the other hand,
  the stellar UV background, which must be chromospheric in origin,
  is less than 1/25th that seen on YZ CMi. This suggests a link between
  chromospheric and coronal heating.

Title: The Goddard High Resolution Spectrograph: Instrument, Goals,
    and Science Results
Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.;
   Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone,
   D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.;
   Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Ake, T. B.; Bruhweiler,
   F.; Cardelli, J. A.; Lindler, D. J.; Malumuth, E.; Randall, C. E.;
   Robinson, R.; Shore, S. N.; Wahlgren, G.
Bibcode: 1994PASP..106..890B
Altcode:
  The Goddard High Resolution Spectrograph (GHRS), currently in Earth
  orbit on the Hubble Space Telescope (HST), operates in the wavelength
  range of 1150-3200A with spectral resolutions (lambda/delta-lambda)
  of approximately 2 X 10^3, 2 X 10^4, and 1 X 10^5. This paper describes
  the instrument and its development from inception, its current status,
  the approach to operations, representative results in the major areas
  of the scientific goals, and prospects for the future. (SECTION:
  Instrumentation and Data Analysis)

Title: GHRS Observations of Cool, Low-Gravity Stars. I. The
    Far-Ultraviolet Spectrum of alpha Orionis (M2 Iab)
Authors: Carpenter, Kenneth G.; Robinson, Richard D.; Wahlgren,
   Glenn M.; Linsky, Jeffrey L.; Brown, Alexander
Bibcode: 1994ApJ...428..329C
Altcode:
  We present far-UV (1200-1930 A) observations of the prototypical red
  supergiant star alpha Ori, obtained with the Goddard High Resolution
  Spectrograph (GHRS) on the Hubble Space Telescope (HST). The
  observations, obtained in both low- (G140L) and medium- (G160/200M)
  resolution modes, unambiguously confirm that the UV 'continuum'
  tentatively seen with (IUE) is in fact a true continuum and is not due
  to a blend of numerous faint emission features or scattering inside
  the IUE spectrograph. This continuum appears to originate in the
  chromospheric of the star at temperatures ranging from 3000-5000 K,
  and we argue that it is not related to previously reported putative
  companions or to bright spots on the stellar disk. Its stellar origin
  is further confirmed by overlying atomic and molecular absorptions from
  the chromosphere and circumstellar shell. The dominant structure in
  this spectral region is due to nine strong, broad absorption bands of
  the fourth-positive A-X system of CO, superposed on this continuum in
  the 1300-1600 A region. Modeling of this CO absorption indicates that it
  originates in the circumstellar shell in material characterized by T =
  500 K, N(CO) = 1.0 x 10<SUP>18</SUP> per sq cm, and V<SUB>turb</SUB>
  = 5.0 km per sec. The numerous chromospheric emission features are
  attributed mostly to fluorescent lines of Fe II and Cr II (both
  pumped by Lyman Alpha) and S I lines, plus a few lines of O I, C I,
  and Si II. The O I and C I UV 2 multiplets are very deficient in flux,
  compared to both the flux observed in lines originating from common
  upper levels but with markedly weaker intrinsic strength (i.e., O I
  UV 146 and C I UV 32) and to the UV 2 line fluxes seen in other cool,
  less luminous stars. This deficiency appears to be caused by strong
  self-absorption of these resonance lines in the circumstellar shell
  and/or upper chromosphere of alpha Ori. Atomic absorption features,
  primarily due to C I and Fe II are clearly seen in the G160M spectrum
  centered near 1655 A. These Fe II features are formed at temperatures
  that can occur only in the chromosphere of the star and are clearly
  not photospheric or circumstellar in origin.

Title: Examining the Corona of HR 1099 with the Hubble Space Telescope
Authors: Robinson, R. D.; Maran, S. P.; Carpenter, K. G.; Brandt,
   J. C.; Linsky, J. L.
Bibcode: 1994AAS...184.0515R
Altcode: 1994BAAS...26Q.865R
  A pilot program for the study of stellar coronae through ultraviolet
  diagnostic lines is in progress with the Goddard High Resolution
  Spectrograph on the Hubble Space Telescope. An initial result of this
  program was the detection of the coronal emission line of Fe XXI at 1354
  Angstroms in the quiescent spectrum of the dMe star AU Mic (ApJ 421,
  800, 1994). The line appeared to be symmetrical, had no measurable
  radial velocity with respect to the stellar rest frame, and had a
  width which was consistent with a thermal gas of temperature 10(7) K,
  suggesting very small turbulence within the formation region. In March
  1994, we observed the RS CVn binary HR 1099 = HD 22468 (K1 IV + G5 IV )
  using instrumental settings identical to those employed with AU Mic,
  but with the added benefit of the recently-installed HST corrective
  optics (COSTAR). Each exposure was bracketed by observations of an
  on-board wavelength calibration lamp. The results of the series of
  eight 27-minute integrations, obtained at one-orbit intervals, will
  be presented and compared with the AU Mic spectrum.

Title: GHRS Observations of the M-Giant MU GEM
Authors: Carpenter, K. G.; Robinson, R. D.; Johnson, H. R.; Ensman,
   L. M.
Bibcode: 1994AAS...184.0505C
Altcode: 1994BAAS...26..863C
  The ultraviolet spectrum of the M-giant mu Gem (M3 IIIab) is sampled
  at selected important wavelengths with the Goddard High Resolution
  Spectrograph (GHRS) on the Hubble Space Telescope (HST). The wavelength
  regions are chosen to include lines sensitive to turbulence and flow
  velocities in the stellar chromosphere and wind acceleration region, as
  well as some fiducial photospheric absorption features. The dynamics of
  the outer atmosphere of mu Gem are examined using the observed profiles
  and positions of chromospheric emission lines of C II, Fe II, Mg II, Fe
  I, referenced to photospheric absorption lines of Fe I. The content of
  the spectra and the inferred flow and turbulent velocities are compared
  to those found for the other cool, low-gravity stars observed with GHRS,
  including alpha Ori (M2 Iab) and gamma Cru (M3.4 III).

Title: Examining the corona of HR 1099 with the Hubble Space
    Telescope.
Authors: Robinson, R. D.; Maran, S. P.; Carpenter, K. G.; Brandt,
   J. C.; Linsky, J. L.
Bibcode: 1994BAAS...26..865R
Altcode:
  No abstract at ADS

Title: HST Observations of the Chromosphere of a Carbon Star
Authors: Ensman, L. M.; Johnson, H. R.; Carpenter, K. G.; Robinson,
   R. D.; Luttermoser, D.
Bibcode: 1994AAS...184.0506E
Altcode: 1994BAAS...26..863E
  Ultraviolet spectra from the first Hubble Space Telescope observations
  of a carbon star are presented, as well as line identifications and an
  initial analysis of the velocity structure of the emitting region. Two
  spectra of UU Aur (HD 46687, type N3; C5,3) have been obtained. In the
  lower-resolution FOS spectrum (2310 -- 3275 Angstroms), UV emission
  lines of Mg I, Mg II, and Fe II, fluoresced lines of Fe I and II,
  semi-forbidden emission from C II, Si II, and Al II, absorption lines of
  Fe I and Ti II, and absorption by CH and CaCl have been identified. In
  the high resolution GHRS spectrum, which covers a 50 Angstroms region
  around the Mg II h and k emission lines, overlying Mg II and Mn I
  absorption and two fluoresced Fe I lines have been resolved. The Mg
  II, and perhaps the Ti II, absorption appears to be interstellar. UV
  emission lines of predominantly singly ionized metals indicate the
  existence of a chromosphere at ~ 5000 K. In UU Aur, the Mg II emission
  clearly arises in material which is flowing away from the star at 35--60
  km/s. Shifts of the Fe II emission lines support the conclusion that
  the chromosphere is expanding at highly supersonic velocities. However,
  overlying Mn I absorption must be due to stationary material further
  out. The forbidden and fluoresced lines also come from a region(s)
  with negligible velocity. These data imply that shocks may form in the
  atmospheres of carbon stars and thus be a mechanism for chromospheric
  heating and mass loss. In fact, previous semi-empirical chromospheric
  models of the carbon star TX Psc (Luttermoser, Johnson, Avrett, and
  Loeser 1989) indicate a similar shock-like velocity field. Luttermoser,
  D., Johnson, H. R., Avrett, G., and Loeser, R. 1989, ApJ 345, 543.

Title: Ultraviolet and Radio Observations of the Young Rapidly
    Rotating k0 Dwarf Star HD197890
Authors: Robinson, R. D.; Carpenter, K. G.; Slee, O. B.; Nelson,
   G. J.; Stewart, R. T.
Bibcode: 1994MNRAS.267..918R
Altcode:
  We present the results of UV observations taken with the International
  Ultraviolet Explorer (IUE) satellite and microwave observations
  obtained with the Australia Telescope during an observing campaign
  of the rapidly rotating K0 dwarf star III) 197890, nicknamed `Speedy
  Mic'. This star was recently recognized as a powerful, transient EUV
  source by the ROSAT WFC, and subsequent investigation showed it to
  be a ZAMS or possibly a PMS dwarf which may be a member of the Local
  Association. Our observations show it to have strong, variable UV
  emission lines near the `saturation' levels. The radio observations
  show a level of `quiescent' emission consistent with other rapidly
  rotating stars, but there is no evidence for the large flux variations
  that normally characterize the time history of such objects.

Title: Observing Stellar Coronae with the Goddard High Resolution
    Spectrograph. I. The dMe Star AU Microscopii
Authors: Maran, S. P.; Robinson, R. D.; Shore, S. N.; Brosius, J. W.;
   Carpenter, K. G.; Woodgate, B. E.; Linsky, J. L.; Brown, A.; Byrne,
   P. B.; Kundu, M. R.; White, S.; Brandt, J. C.; Shine, R. A.; Walter,
   F. M.
Bibcode: 1994ApJ...421..800M
Altcode:
  We report on an observation of AU Mic taken with the Goddard High
  Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope. The
  data consist of a rapid sequence of spectra covering the wavelength
  range 1345-1375 A with a spectral resolution of 10,000. The observations
  were originally intended to search for spectral variations during
  flares. No flares were detected during the 3.5 hr of monitoring. A
  method of reducing the noise while combining the individual spectra
  in the time series is described which resulted in the elimination of
  half of the noise while rejecting only a small fraction of the stellar
  signal. The resultant spectrum was of sufficient quality to allow the
  detection of emission lines with an integrated flux of 10<SUP>-15</SUP>
  ergs/sq cm(sec) or greater. Lines of C I, O I, O V, Cl I, and Fe XXI
  were detected. This is the first indisputable detection of the 1354
  A Fe XXI line, formed at T approximately = 10<SUP>7</SUP> K, on a
  star other than the Sun. The line was well resolved and displayed
  no significant bulk motions or profile asymmetry. From the upper
  limit on the observed line width, we derive an upper limit of 38 km/s
  for the turbulent velocity in the 10<SUP>7</SUP> K plasma. An upper
  limit is derived for the flux of the 1349 A Fe XII line, formed at T
  approximately = 1.3 x 10<SUP>6</SUP> K. These data are combined with
  contemporaneous GHRS and International Ultraviolet Explorer (IUE) data
  to derive the volume emission measure distribution of AU Mic over the
  temperature range 10<SUP>4</SUP>-10<SUP>7</SUP> K. Models of coronal
  loops in hydrostatic equilibrium are consistent with the observed
  volume emission measures of the coronal lines. The fraction of the
  stellar surface covered by the footprints of the loops depends upon the
  loop length and is less than 14% for lengths smaller than the stellar
  radius. From the upper limit to the estimated width of the Fe XXI line
  profile we find that the we cannot rule out Alfven wave dissipation
  as a possible contributor to the required quiescent loop heating rate.

Title: Search for CO Absorption Bands in IUE Far-Ultraviolet Spectra
    of Cool Stars
Authors: Gessner, S. E.; Carpenter, K. G.; Robinson, R. D.
Bibcode: 1994AJ....107..747G
Altcode:
  Observations of the red supergiant (M2 Iab) alpha Ori with the Goddard
  High Resolution Spectrograph (GHRS) on board the Hubble Space Telescope
  (HST) have provided an unambiguous detection of a far-ultraviolet
  (far-UV) chromospheric continuum on which are superposed strong
  molecular absorption bands. The absorption bands have been identified
  by Carpenter et al. (1994) with the fourth-positive A-X system of
  CO and are likely formed in the circumstellar shell. Comparison of
  these GHRS data with archival International Ultraviolet Explorer
  (IUE) spectra of alpha Ori indicates that both the continuum and
  the CO absorption features can be seen with IUE, especially if
  multiple IUE spectra, reduced with the post-1981 IUESIPS extraction
  procedure (i.e., with an oversampling slit), are carefully coadded
  to increase the signal to noise over that obtainable with a single
  spectrum. We therefore initiated a program, utilizing both new and
  archival IUE Short Wavelength Prime (SWP) spectra, to survey 15 cool,
  low-gravity stars, including alpha Ori, for the presence of these two
  new chromospheric and circumstellar shell diagnostics. We establish
  positive detections of far-UV stellar continua, well above estimated
  IUE in-order scattered light levels, in spectra of all of the program
  stars. However, well-defined CO absorption features are seen only in
  the alpha Ori spectra, even though spectra of most of the program stars
  have sufficient signal to noise to allow the dectection of features of
  comparable magnitude to the absorptions seen in alpha Ori. Clearly if
  CO is present in the circumstellar environments of any of these stars,
  it is at much lower column densities.

Title: A Search For Microflaring Activity on dMe Flare Stars
Authors: Robinson, R. D.; Carpenter, K. G.; Percival, J. W.
Bibcode: 1994ASPC...64..456R
Altcode: 1994csss....8..456R
  No abstract at ADS

Title: GHRS Observations and Analysis of the 0 I and C I Resonance
    Lines in the UV Spectrum of alpha ORI (M2 Iab)
Authors: Carpenter, Kenneth G.; Robinson, Richard D.; Judge, Philip
   G.; Ebbets, Dennis C.; Brandt, John C.
Bibcode: 1994ASPC...64...56C
Altcode: 1994csss....8...56C
  No abstract at ADS

Title: Coordinated Space and Ground-Based Observations of the Flare
    Star YZ CMi
Authors: Carpenter, Kenneth G.
Bibcode: 1994iue..prop.4768C
Altcode:
  We propose IUE ultraviolet observations of the flare star YZ CMi to
  complement high time resolution data to be acquired with the Goddard
  High Resolution Spectrograph on Hubble Space Telescope and other
  ground and space-based observatories including the AAT, ROSAT, and
  EUVE. The HST observations are designed to search for the signature
  of downflowing proton beams during flare events and to estimate their
  importance in providing the energy that powers the flare. These IUE
  observations, which include the full range of transition region and
  chromospheric lines, are critical to determining the energy balance
  and atmospheric structure of any flare observed. The extended dataset,
  including non-flare spectra, will allow us to characterize the overall
  activity level of the star at the time of the observations, and thus
  place the events in the proper context.

Title: The Chromosphere of Alpha Tau - Cycle 4 Medium
Authors: Carpenter, Kenneth
Bibcode: 1994hst..prop.5358C
Altcode: 1994hst..prop.1804C
  We propose observations of the K5 III star Alpha Tau using the Goddard
  High-Resolution Spectrograph (GHRS), to follow-up on the exciting
  initial SAO observations of this star and the SV observations of the
  K5 III hybrid star Gamma Dra. These data will also allow a detailed
  comparison of its spectrum and the thermodynamic properties of its
  outer atmosphere with those of the cooler M giant and supergiant
  stars Gamma Cru and Alpha Ori, observed during previous cycles. We
  shall check for variations in the C II downflow discovered in the
  SAO observations and search for evidence of systematic flows in
  other emission lines. We shall make detailed comparisons of the
  chromospheric emission lines and wind signatures in the UV spectra
  of two stars of the same spectral class, where one is a hybrid and
  one is not. We shall search for evidence of shocks and/or propagating
  waves in the line variations predicted by our recent calculations. We
  will also determine the variation of wind velocity with height using
  semi-empirical non-LTE models assuming spherical symmetry, search for
  evidence of circumstellar and interstellar absorptions on resonance
  lines of O I, Fe II, and Mg II, and compare the short-wavelength
  continuum measured in this star with that detected in observations of
  Gamma Dra, Gamma Cru and Alpha Ori.

Title: Spectra and Chromospheres of Carbon and M Stars - CYCLE4 Medium
Authors: Carpenter, Kenneth
Bibcode: 1994hst..prop.5359C
Altcode: 1994hst..prop.1805C
  We propose to use the Faint Object Spectrograph (FOS) and the Goddard
  High-Resolution Spectrograph (GHRS) on the HST to obtain ultraviolet
  spectra of visually bright N-type carbon stars and late M-giant
  stars. These spectra, obtainable only with HST, will be used with
  theoretical models to infer the temperature and density structure and
  the velocity fields of the outer atmosphere in these evolutionarily
  advanced, non-mira giants. In anticipation of this effort, we have
  already pushed IUE to its limit to obtain both low-resolution, and,
  where possible, high-resolution spectra of several M, S, and C stars,
  and these have been analyzed and published. Based upon the observed
  line profiles and continua, we will construct semi-empirical non-LTE
  models in both plane-parallel geometry and spherical geometry, including
  velocity fields, by attaching a chromosphere to theoretical photospheric
  models. Two-component models will be studied. Using these and ab-initio
  hydrodynamic models, we will examine the mechanisms responsible
  for chromospheric heating and mass loss. A full range of supporting
  ground-based observations will be undertaken to permit us to connect
  models of the photospheres, chromospheres, and circumstellar shells.

Title: On the Weakness of C I and O I Resonance Line Emission from
    the Chromosphere of alpha Ori.
Authors: Carpenter, K.; Robinson, R.; Judge, P.; Ebbets, D.; Brandt, J.
Bibcode: 1993AAS...183.1504C
Altcode: 1993BAAS...25Q1313C
  The resonance lines from multiplets UV 2 of both O I and C I are
  typically quite strong in emission in the far-UV spectrum of cool
  stars. However, in the prototypical M-supergiant alpha Ori, these lines
  are remarkably weak, although other transitions from the same upper
  energy levels, O I (UV 146) and C I (UV 32), are observed in strong
  emission despite their much weaker intrinsic strengths. Due to the
  presence of many lines from other species in the regions around the UV
  2 multiplets of O I and C I near 1302 Angstroms and 1655 Angstroms, the
  lines of interest suffer severe blending and progress in understanding
  this flux deficiency is difficult based on low resolution IUE and
  GHRS data. We have therefore obtained medium resolution (R=10,000)
  GHRS spectra of alpha Ori of these complex spectral regions, as well
  as the regions around the O I (UV 146) and C I (UV 32) lines near 1640
  Angstroms and 1993 Angstroms, respectively, to resolve the various
  contributors and allow detailed study of this phenomenon. In this
  paper, we present the spectra and discuss the formation of the O I,
  C I, Fe II, and S I lines which they clearly resolve. Semi-empirical
  modeling of the outer atmosphere of alpha Ori and detailed radiative
  transfer calculations are used to study the creation and destruction
  of O I and C I photons.

Title: A Search for Proton Beams during Flares on AU Microscopii
Authors: Robinson, R. D.; Carpenter, K. G.; Woodgate, B. E.; Maran,
   S. P.
Bibcode: 1993ApJ...414..872R
Altcode:
  We report the results of a coordinated observing campaign on the active
  M dwarf star AU Mic. The purpose of the campaign was to search for
  evidence of proton beams during the impulsive phase of stellar flares
  and to determine whether the energy contained in these beams represented
  a significant fraction of the energy budget of the flare. During a total
  of 3.5 hr of monitoring a small flare was observed simultaneously by
  the HST, IUE, and the AAT. This event, which had a total optical + UV
  emission of 1.3 x 10 exp 32 ergs, occurred during the decay phase of
  a much larger event and showed no evidence for a proton beam with an
  energy greater than a few times 10 exp 29 ergs/s. This is comparable
  to the maximum energy flux released by the flare, though this energy
  release rate must occur over a time interval much shorter than that
  of the impulsive phase itself. We conclude that the proton beams may
  be capable of transporting some energy during the impulsive phase
  of a flare, but that they are unlikely to be the major contributor,
  at least for this particular event.

Title: GHRS Observations of the M-giant gamma CRU
Authors: Carpenter, K.; Robinson, R.; Gessner, S.
Bibcode: 1993AAS...182.4613C
Altcode: 1993BAAS...25..875C
  The Goddard High Resolution Spectrograph (GHRS) on the Hubble Space
  Telescope has been used to obtain medium (R=20,000) and high (R=85,000)
  resolution UV spectra of chromospheric emission features for the M3.4
  III star gamma Cru. Large Science Aperture (LSA), medium resolution
  spectra were obtained to survey the 1980 - 2200 Angstroms region with
  good signal-to-noise. Small Science Aperture (SSA) G270M and Echelle-B
  spectra of selected longer wavelength regions were obtained to allow
  the measurement of velocity flows and turbulence for a variety of ions,
  including C II, Fe II, Co II, Si I/II, Ni II, Mn II, and Mg II. Gaussian
  fits to the optically thin C II (UV 0.01) intercombination lines and
  fluorescently-excited lines of Co II, Ni II, Fe II, and Si I indicate
  average turbulent velocities (Doppler FWHM) of 30.2 and 28.6 km/s,
  respectively. For comparison, the C II turbulent velocity previously
  measured for the K5 giant alpha Tau is ~ 24 km/s. The measured radial
  velocities of the fluorescent lines average 21.5 km/s, which places them
  basically at rest relative to the radial velocity of the star (21 km/s),
  while the C II lines average 23.1 km/s, a modest inflow of a couple of
  km/s. A subset of the collisionally-excited Fe II emission lines show
  an average radial velocity of 22.6 km/s, also a very modest inflow,
  at best. The stronger Fe II lines exhibit a more complex profile which
  consists of a broad emission line with an ~ 40 km/s FWHM, on which are
  superposed two absorption components. The stronger component appears at
  relatively low radial velocity (in the 7 - 15 km/s range) in each line,
  with a mean value over the sample of ~ 10.5 km/s, while the weaker
  component appears at relatively high radial velocity in each line (in
  the range from 25 to 34 km/s), with a mean value of ~ 31.3 km/s. The
  first represents an outflow of about 10 km/s, while the second an
  inflow of about 10 km/s. The Mg II h and k emission lines also show
  the dual-absorption structure seen in the Fe II lines. However, both
  the emission and absorption components in the k-line are red-shifted
  by 7 to 9.5 km/s, relative to their equivalent components in the h-line.

Title: MG II H and K Profiles in Luminous, Cool Stars
Authors: Robinson, R. D.; Carpenter, K. G.
Bibcode: 1993AAS...182.4619R
Altcode: 1993BAAS...25..877R
  As part of an investigation of the velocity fields in the atmospheres of
  cool, luminous stars we used the Goddard High Resolution Spectrograph
  (GHRS) aboard the Hubble Space Telescope to obtain a high resolution
  spectrum of the Mg II h and k lines in the M supergiant alpha Ori. These
  strong, centrally reversed emission lines have been well studied by the
  IUE. While the h line in alpha Ori has nearly equal intensity in the red
  and blue peaks, the blue peak of the k line is always much weaker than
  the red peak. This asymmetry is normally explained as resulting from
  absorption by Fe I and Mn I in the circumstellar shell. An examination
  of the GHRS spectrum, however, reveals that the asymmetry results from
  a velocity shift between the emission wings and the central absorption
  core of the line. Further, while the central absorption profiles for
  the h and k lines agree very well when plotted on a velocity scale, the
  centroid of the k line emission wings was observed to be redshifted by
  approximately 23 km/s with respect to that of the h line. Examination
  of other high resolution GHRS observations of Mg II showed a similar,
  though less pronounced, relative redshift of the k line centroid on
  the normal M giant gamma Cru and the hybrid K giant gamma Dra. To date,
  no concrete model has been proposed to explain these shifts. Examining
  well exposed, high resolution IUE observations of alpha Ori shows a
  close agreement with the GHRS results. This gives us confidence that
  we can use IUE spectra to study the relative shapes and velocities
  of the Mg II h and k lines and we are currently involved in a program
  to use the IUE archive to quantify the behavior of the Mg II h and k
  profiles as a function of luminosity and spectral type for luminous,
  cool stars. The results of this program will be presented.

Title: A Search for CO Absorption Bands in IUE Spectra of Cool Stars
Authors: Gessner, S.; Carpenter, K.; Robinson, R.
Bibcode: 1993AAS...182.4612G
Altcode: 1993BAAS...25..875G
  Observations of the red supergiant (M2 Iab) alpha Ori with the Goddard
  High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope
  (HST) have provided an unambiguous detection of a far-UV continuum on
  which are superposed strong molecular absorption bands (Carpenter 1991,
  ASP Conf. Ser. 26, p. 17). The continuum is formed in the stellar
  chromosphere. The absorption bands, which appear in the 1300 - 1600
  Angstroms spectral region, have been identified with the (n,0) bands
  (n=0,...,8) of the 4th-positive A-X system of CO and are likely
  formed in the circumstellar shell. Comparison of these GHRS data
  with archival IUE spectra indicates that both the continuum and the
  CO absorption features can be seen with IUE, especially if multiple
  IUE spectra, reduced with the post-1981 IUESIPS extraction procedure
  (i.e., with an oversampling slit), are carefully co-added to increase
  the signal-to-noise over that obtainable with a single spectrum. We
  have therefore begun a program, utilizing both new and archival IUE
  spectra, to survey other cool, low-gravity stars for the presence of
  these two new chromospheric and circumstellar shell diagnostics. We hope
  to identify promising targets for examination with HST spectrographs
  at the higher resolution and signal-to-noise needed for quantitative
  analysis. The initial results of this IUE survey are presented here.

Title: Observations of 3C 273 With the Goddard High Resolution
    Spectrograph on the Hubble Space Telescope
Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, E. A.;
   Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone,
   D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.;
   Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Snow, M.; Randall,
   C. E.; Lindler, D. J.; Shore, S. N.; Morris, S. L.; Gilliland, R. L.;
   Lu, L.; Robinson, R. D.
Bibcode: 1993AJ....105..831B
Altcode:
  The observations of the quasar 3C 273 taken with the Goddard High
  Resolution Spectrograph in 1991 February are presented here. We have
  included both the reduced raw data, and smoothed and deconvolved
  spectra. Also, a list of observed absorption lines is presented. The
  data comprise 11 spectra, including 1 low resolution observation and 10
  medium resolution observations. The wavelength region covered ranged
  from about 1150 to 2820 A, but was not all inclusive. The procedures
  used to obtain and reduce the data, including corrections for fixed
  pattern noise, compensation for the effects of spherical aberration
  in the HST primary mirror, and objective detection of weak absorption
  lines, are described. We also have included a short discussion on the
  detection of galactic Ni II and Virgo cluster metal lines.

Title: Atomic data needs for the analysis of the ultraviolet spectrum
    of cool stars.
Authors: Carpenter, K. G.
Bibcode: 1993PhST...47..139C
Altcode:
  A brief introduction to the UV spectra of cool stars is given, followed
  by a review of astronomical observatories and instruments which
  are capable of acquiring UV spectral data on cool stars. Examples
  of observational data are presented, along with a description of
  typical analysis performed on such data. The basic atomic data needed
  to perform these analysis are summarized, with the most important UV
  multiples or transitions of the most relevant ions identified.

Title: CO Molecular Absorption in Far-UV Spectra of Cool Stars
Authors: Carpenter, Kenneth G.
Bibcode: 1993iue..prop.4498C
Altcode:
  We propose a far-UV survey of cool giant and supergiant stars to search
  for evidence of circumstellar absorption by the CO molecule. This
  survey is motivated by the discovery of a far-UV continuum and
  superposed circumstellar CO absorption in a spectrum of alpha Ori (M2
  Iab) obtained with HST and the subsequent demonstration that IUE is
  capable of detecting these bands. These bands are an excellent probe
  of the circumstellar regions of such stars, and provide diagnostics
  of layers not well sampled by other techniques. Where possible, very
  rough estimates of the conditions in the regions represented by the CO
  absorption will be obtained on the basis of these IUE data. The results
  of this survey will then be used to select targets /individual bands
  for observation at higher resolution with the GHRS/HST to allow detailed
  comparison with models and more precise determinations of temperatures
  and column densities in the circumstellar environment of these stars.

Title: Observations of a Flare on AU MIC
Authors: Robinson, R. D.; Carpenter, K. G.; Woodgate, B. E.
Bibcode: 1992AAS...181.5104R
Altcode: 1992BAAS...24.1206R
  We report the results of a coordinated observing campaign of the active
  dMe flare star AU Mic, carried out on 1992 Sept 9. Participating
  instruments include the HST and IUE satellites and the 3.9m
  Anglo-Australian Telescope. During this campaign a long duration,
  1.5 mag (U band) flare was detected, with the maximum phase observed
  simultaneously with the IUE and AAT and the decay phase monitored by
  all three instruments. The AAT observations consisted of a time series
  of CCD exposures covering the wavelength range 3650-4450 Angstroms
  and having a temporal resolution of 6 seconds. The impulsive phase
  lasted for about 1 minute and was therefore well resolved by these
  observations. The flare showed pronounced broadening of the Balmer
  series, with the Balmer line fluxes increasing with the continuum
  during the impulsive phase but having a much longer decay time. A
  pronounced HeII (4026 Angstroms ) emission was seen during the flare,
  with some indication that this line increased in absorption strength
  about 30 seconds before the continuum increase. The CaII H and K lines
  decreased in strength during the impulsive and early decay phase of the
  event, but recovered during the later decay phase. A low resolution LWP
  exposure was taken by the IUE during the peak of the flare. Combining
  this with the optical data gives an almost complete coverage of the
  flare spectrum from 2200 to 4500 Angstroms . We discuss the implications
  of these observations in relation to current flare models.

Title: The Search for Acoustically-Driven Mass-Loss in Evolved Stars
Authors: Stencel, R. E.; Brown, A.; Carpenter, K. G.; Cuntz, M.;
   Judge, P.
Bibcode: 1992AAS...181.3603S
Altcode: 1992BAAS...24.1175S
  Recent ab-initio calculations of stochastic stellar wind models by
  Cuntz (1992 in Cool Stars VII, ASP Conf. Ser. 26, p.383) have proven
  remarkably robust in predicting observed chromospheric flow patterns
  including possible variabilities with time in selected cool, evolved
  stars. The calculations solve the equations of hydrodynamics using
  the method of characteristics and assume: (i) saw-tooth shock wave
  profiles, and (ii) wave periods were changed stochastically while
  keeping the wave amplitudes constant (see Cuntz 1990 Ap.J. 349,
  p.141). Among the results of fitting chromospheric flow velocities is
  the implication that the permitted range of acoustic wave periods for
  a given star is constrained. We made use of the IUE satellite during
  August and September 1992 to repeatedly observe two stars, the yellow
  giant Aldebaran (K5 III) and the red supergiant, Betelgeuse (M2 Iab),
  in order to sample variations in their atmospheres on timescales of ~
  10(4) to ~ 10(6) seconds, which bracket the predicted mean acoustic wave
  periods for these objects. In particular, we obtained deep exposures
  in order to measure density-sensitive line ratios within the C II]
  intercombination features near 2325A (cf. Lennon et al. 1985 Ap.J. 294,
  p.200) to test the hypothesis that density fluctuations could be
  measured as a consequence of these acoustic waves. The results of
  these observations will be presented and discussed in terms of the
  number and amplitude of acoustic waves contributing to chromospheric
  heating and mass loss from these stars, as well as the wave origins in
  the evolving oscillatory structure of these stellar interiors. We are
  pleased to acknowledge IUE--NASA grant NAG5-2103 for partial support
  of this effort.

Title: Detection of a Proton Beam during the Impulsive Phase of a
    Stellar Flare
Authors: Woodgate, Bruce E.; Robinson, Richard D.; Carpenter, Kenneth
   G.; Maran, Stephen P.; Shore, Steven N.
Bibcode: 1992ApJ...397L..95W
Altcode:
  A transient event consistent with the predicted temporal and spectral
  signatures of an energetic proton beam was detected in the impulsive
  phase of a small flare on the red dwarf star AU Microscopii. It
  consisted of a prominent increase in the flux in the red wing of
  Lyman-alpha near 1223 A, simultaneously with the peak of a flare
  observed in the 1206 A transition region line of Si III. The probability
  that the red wing event was a chance fluctuation is one chance in
  2.5 x 10 exp 4. This observation represents a confirmation of the
  prediction by Orrall and Zirker (1976) in which downstreaming protons
  accelerated during the impulsive phase of a flare charge exchange with
  ambient neutral hydrogen and emit Lyman-alpha radiation from 1 to 15
  A redward of line center.

Title: The Ultraviolet Photospheric Spectrum of Alpha Orionis
Authors: Wahlgren, G. M.; Robinson, R. D.; Carpenter, K. G.
Bibcode: 1992AAS...18110010W
Altcode: 1992BAAS...24.1280W
  No abstract at ADS

Title: Plasma Flows in the Outer Atmosphere of α Ori
Authors: Carpenter, K.; Robinson, R.; Wahlgren, G.; Brandt, J.;
   Linsky, J.; Ebbets, D.; Weymann, R.
Bibcode: 1992AAS...181.5111C
Altcode: 1992BAAS...24.1207C
  No abstract at ADS

Title: Detection of a Proton Beam during the Impulsive phase of a
    Stellar Flare
Authors: Woodgate, B. E.; Robinson, R. D.; Carpenter, K. G.; Maran,
   S. P.; Shore, S.
Bibcode: 1992AAS...180.3010W
Altcode: 1992BAAS...24..777W
  We present evidence for the detection of a proton beam during the
  impulsive phase of a flare on the Dme star AU Microscopii. At 1991
  Sept 3 04h 56m 10s UT, the Goddard High Resolution Spectrograph on the
  Hubble Space Telescope observed an increase in the flux in the red
  wing of the hydrogen Lyman alpha line at 1223A, unaccompanied by an
  increase in the blue wing, simultaneously with an increase in the flux
  of the SiIII 1206A transition region line. The 1223A flux increase was
  2.2 x 1027 ergs s-1 A-1, with 3s duration. The chance probability of
  the observation is 1 in 105. This effect was predicted by Orrall and
  Zirker (1976), as a downstreaming beam of protons charge exchanging
  with ambient neutral hydrogen and emitting Lyman alpha radiation at
  the downstreaming velocity. The energy in the beam is estimated as 7
  x 1029 ergs s-1.

Title: A Search for Short-Timescale Variations in the Chromosphere;
    UV Spectrum of the M-Giant Gamma Crucis
Authors: Cheng, K. -P.; Carpenter, K. G.
Bibcode: 1992ASPC...26...43C
Altcode: 1992csss....7...43C
  No abstract at ADS

Title: The Chromosphere and Circumstellar Shell of α Orionis as
    Observed with the Goddard High Resolution Spectrograph
Authors: Carpenter, K. G.; Robinson, R. D.; Wahlgren, G. M.; Linsky,
   J. L.; Brown, A.
Bibcode: 1992ESOC...44..387C
Altcode: 1992swhs.conf..387C
  No abstract at ADS

Title: Detection of a Proton Beam during the Impulsive Phase of a
    Stellar Flare
Authors: Robinson, R. D.; Woodgate, B. E.; Carpenter, K. G.; Maran,
   S. P.; Shore, S. N.
Bibcode: 1992ESOC...44..447R
Altcode: 1992swhs.conf..447R
  No abstract at ADS

Title: Late-Type Stars (Invited Review)
Authors: Carpenter, K. G.
Bibcode: 1992ASPC...26...17C
Altcode: 1992csss....7...17C
  No abstract at ADS

Title: A Search for CO Molecular Absorption in Far-UV Spectra of
    Cool Stars
Authors: Carpenter, Kenneth G.
Bibcode: 1992iue..prop.4214C
Altcode:
  We propose a far-UV survey of cool giant and supergiant stars to search
  for evidence of circumstellar absorption by the CO molecule. This
  survey is motivated by the discovery of a far-UV continuum and
  superposed circumstellar CO absorption in a spectrum of alpha Ori (M2
  lab) obtained with HST and the subsequent demonstration that IUE is
  capable of detecting these bands. These bands are an excellent probe
  of the circumstellar regions of such stars, and provide diagnostics
  of layers not well sampled by other techniques. Where possible, very
  rough estimates of the conditions in the regions represented by the CO
  absorption will be obtained on the basis of these IUE data. The results
  of this survey will then be used to select targets/individual bands for
  observation at higher resolution with the GHRS/HST to allow detailed
  comparison with models and more precise determinations of temperatures
  and column densities in the circumstellar environment of these stars.

Title: HST Observations of the Flare Star AU MIC
Authors: Robinson, R. D.; Shore, S. N.; Carpenter, K. G.; Woodgate,
   B. E.; Maran, S. P.; Brandt, J. C.; Kundu, M. R.; White, S. M.;
   Linsky, J. L.; Walter, F. M.
Bibcode: 1992ASPC...26...31R
Altcode: 1992csss....7...31R
  No abstract at ADS

Title: Molecular Absorption in the UV Spectrum of A ORI
Authors: Wahlgren, G. M.; Robinson, R. D.; Carpenter, K. G.
Bibcode: 1992ASPC...26...37W
Altcode: 1992csss....7...37W
  No abstract at ADS

Title: Chromospheres and winds of cool stars
Authors: Carpenter, K. G.
Bibcode: 1992HiA.....9..477C
Altcode:
  No abstract at ADS

Title: Simultaneous IUE/HST-GHRS Observations of AU MIC
Authors: Carpenter, Kenneth G.
Bibcode: 1992iue..prop.4212C
Altcode:
  We propose to monitor the early dwarf-M flare star and BY Dra
  variable AU Mic over two IUE shifts approximately centered on the
  time of HST observations with the GHRS. The GHRS observations are
  part of a Cycle 1 HST GO program that is to be reexecuted in late
  summer of 1992, due to an intermittent HST instrument failure during
  the initial execution of the HST program in September 1991. The GHRS
  observations cover a single, very narrow range of wavelengths (36 A)
  containing Lyman-alpha, Si III 1206 A, and O V 1218 A. They will be
  obtained at very high time resolution (0.4 sec/integration) and are
  designed to look for evidence of proton downflow during the impulsive
  phase of a flare. We request simultaneous IUE observations to place
  the HST observations in a broader context, which will include a wider
  variety of chromospheric and transition region lines and their behavior
  over a 16 hour period approximately centered on the time of the GHRS
  observations. IUE data is critically needed during flare detections
  by HST, so that the radiative losses in the UV can be estimated and
  compared to the energy carried in the proton downflow, in order to
  evaluate the importance of this energy source to the flare.

Title: Zeta-Aurigae Type Binaries
Authors: Carpenter, K. G.
Bibcode: 1992IAUS..151...51C
Altcode:
  No abstract at ADS

Title: SI II emission line diagnostics.
Authors: Judge, P. G.; Carpenter, K. G.; Harper, G. M.
Bibcode: 1991MNRAS.253..123J
Altcode:
  The present study compares ratios of Si II UV emission lines in a
  variety of objects with computations based on recently published
  collisional data of Dufton and Kingston (1991). A high-quality
  spectrum of Alpha Tau (K5 III) obtained by Carpenter et al. (1991) is
  analyzed using the G270M mode of the GHRS on the HST, in addition to
  high-dispersion data from Skylab and IUE. Agreement between observation
  and theory is satisfactory for most lines. A blend with a line of
  Ni II accounts partially for the discrepancies and solves a problem
  with semiforbidden S II emission measures. Disagreement exists between
  certain observed flux ratios and computed values using recent atomic
  data for the intersystem lines. The discrepancy is most significant
  for Alpha Tau. The computed atomic collision strengths within the
  intersystem multiplet itself are argued as a possible cause of the
  discrepancy.

Title: An Investigation of the Flare Star AU Mic with the Goddard
    High Resolution Spectrograph on the Hubble Space Telescope
Authors: Maran, S. P.; Woodgate, B. E.; Carpenter, K. G.; Robinson,
   R. D.; Shore, S. N.; Linsky, J. L.; Brown, A.; Byrne, P. B.; Kundu,
   M. R.; White, S.; Brandt, J. C.; Shine, R. A.; Walter, F. M.
Bibcode: 1991BAAS...23.1382M
Altcode:
  No abstract at ADS

Title: Coordinated IUE/HST Observations of the Flare Star AU mic:
    Results from IUE
Authors: Carpenter, K. G.; Maran, S. P.; Brown, A.; Linsky, J. L.;
   Robinson, R. D.; Byrne, P. B.; Judge, P. G.
Bibcode: 1991BAAS...23.1383C
Altcode:
  No abstract at ADS

Title: Molecular Absorption in the Ultraviolet Spectrum of Alpha Ori
Authors: Wahlgren, G. M.; Robinson, R. D.; Carpenter, K. G.
Bibcode: 1991BAAS...23.1386W
Altcode:
  No abstract at ADS

Title: Time Resolved Observations of the Lyman-Alpha Region in AU
    Mic with the Goddard High Resolution Spectrograph
Authors: Woodgate, B. E.; Maran, S. P.; Carpenter, K. G.; Robinson,
   R. D.; Shore, S. N.; Linsky, J. L.; Byrne, P. B.; Kundu, M. R.
Bibcode: 1991BAAS...23.1383W
Altcode:
  No abstract at ADS

Title: First Results from the Goddard High-Resolution Spectrograph:
    The Chromosphere of alpha Tauri
Authors: Carpenter, Kenneth G.; Robinson, Richard D.; Wahlgren,
   Glenn M.; Ake, Thomas B.; Ebbets, Dennis C.; Linsky, Jeffrey L.;
   Brown, Alexander; Walter, Frederick M.
Bibcode: 1991ApJ...377L..45C
Altcode:
  The K5 III star Alpha Tau was observed with the Goddard High Resolution
  Spectrograph on November 27, 1990 as part of the Science Assessment
  Program for the HST. The spectra show intersystem and permitted
  chromospheric emission lines of semiforbidden C II and Si II, Fe II,
  Fe I, Ni II, and Co II. Resolved profiles of the semiforbidden C II
  lines indicate a complex chromospheric turbulent velocity distribution
  with mean value of roughly 24 km/s, while their observed wavelengths
  indicate a 4 km/s downflow of the semiforbidden C II plasma. Twenty-five
  new emission lines have been found in the 2320-2370 A region, 17 of
  which have been identified with the aid of Skylab data obtained above
  the solar limb, including four lines from Co II (UV 8) and an Fe I
  (UV 12) line.

Title: Physical Conditions and Velocity Structures in the Red Giant
    Winds in the Binaries CI CYG and EG and -- Cycle 2
Authors: Carpenter, Kenneth
Bibcode: 1991hst..prop.3934C
Altcode:
  This proposal represents a two pronged attack aimed at understanding the
  detailed chracteristics of red giant winds in binary star systems. Red
  giant winds can provide the most massive, sustained form of mass
  transfer in binaries. The symbiotic and related stars, which contain
  red giant and hot companion stars, permit line of sight studies through
  a range of red giant atmospheric heights. The goal of this work is to
  attempt to define both the mechanism of rapid mass loss in red giant
  stars and the details of mass transfer to the companion stars. Such
  results can provide important constraints for both stellar and binary
  evolution theories. In each case we expect to derive density and
  temperature values for the red giant wind region and compare this to the
  present understanding of single star conditions where low temperature,
  dust and molecule forming, circumstellar envelopes prevail.

Title: Revised Faint Target/bright Neighbor Test
Authors: Carpenter, Kenneth
Bibcode: 1991hst..prop.3416C
Altcode:
  Verify capability of HRS to detect weak emission despite immediate
  proximity of a bright source. Measure near-angle scattering into HRS
  apertures from adjacent bright source. Revised July 24, 1991 by DCE
  to complete sequences lost during April 91 execution when carrousel
  safed. Revised March 1992 BY DCE for SSA G160M 1300 only

Title: GHRS Spectroscopy of Cool Stars. II.
Authors: Brown, A.; Linsky, J.; Carpenter, K.; Robinson, R.; Ebbets, D.
Bibcode: 1991BAAS...23R.910B
Altcode: 1991BAAS...23..910B
  No abstract at ADS

Title: GHRS Far-Ultraviolet Spectra of the Coronal Giant Capella
    Binary
Authors: Linsky, J. L.; Brown, A.; Carpenter, K.; Robinson, R.
Bibcode: 1991BAAS...23..910L
Altcode:
  No abstract at ADS

Title: GHRS Spectroscopy of Cool Stars. I.
Authors: Carpenter, K.; Robinson, R.; Ebbets, D.; Brown, A.; Linsky, J.
Bibcode: 1991BAAS...23..910C
Altcode:
  No abstract at ADS

Title: GHRS / Goddard High Resolution Spectrograph / Far Ultraviolet
    Spectra of Coronal and Noncoronal Stars - Capella and Gamma-Draconis
Authors: Linsky, J. L.; Brown, A.; Carpenter, K. G.
Bibcode: 1991fyho.conf...70L
Altcode:
  No abstract at ADS

Title: Ghrs/ Goddard High Resolution Spectroscopy Chromospheric
    Emission Line Spectra of the Red Giant Alpha-Tauri
Authors: Carpenter, K. G.; Robinson, R. D.; Ebbets, D. C.; Brown,
   A.; Linsky, J. L.
Bibcode: 1991fyho.conf..212C
Altcode:
  No abstract at ADS

Title: Simultaneous IUE/HST-GHRS Observations of AU MIC
Authors: Carpenter, Kenneth G.
Bibcode: 1991iue..prop.3944C
Altcode:
  We propose to monitor the early dwarf-M flare star and BY Dra variable
  AU Mic over a two day period centered on the time of HST observations
  with the GHRS. The GHRS observations are part of the GHRS Investigation
  Definition Teams's Guaranteed Time Observing (GTO) program and are
  already approved. The GHRS observations cover a single, very narrow
  range of wavelengths (1342 - 1378 A) and their prime purpose is to
  detect and measure lines formed in the corona and in coronal flares,
  such as Fe XXI 1354 A and Fe XII 1349 A, that are too weak to be
  observed by IUE, along with a single transition region line (0 V)
  and lines from one chromospheric ion (C 1). We request simultaneous
  IUE observations to place the HST observations in a broader context,
  which will include a wider variety of chromospheric and transition
  region lines and their behavior over a 48 hour period approximately
  centered on the time of the GHRS observations. The GHRS observations
  are to be scheduled during HST Cycle 0, which (based on a December 1989
  launch) covers the period February 15 - July 15, 1990 and could occur
  during either the 12th or 13th IUE observing episodes. This proposal
  is thus for two years, but all the NASA and ESA shifts are required
  to be contiguous and at a time which will overlap the HST observations.

Title: Alpha Orionis GHRS Team Project -- Cycle 1
Authors: Carpenter, Kenneth
Bibcode: 1990hst..prop.1199C
Altcode:
  The HRS will be used to obtain high signal/noise spectra of the 1980 -
  3300 A spectral region of the M2 Iab supergiant Alpha Orionis. This
  full wavelength region will be observed at medium resolution,
  while 3 selected wavelength regions will be observed in the echelle
  mode. Exposure times have been chosen so that both the chromospheric
  emission line spectrum and the photospheric continuum and absorption
  line spectrum will be properly exposed. These observations will be
  combined and published in atlas format. It is hoped that this atlas
  will provide a standard against which high-resolution UV observations
  of other late-type stars can be compared. Detailed analysis of these
  data are planned by various IDT members.

Title: Physical Conditions and Velocity Structures in the Red Giant
    Winds in the Binaries CI CYG and EG and -- Repeat for HOPR#67
Authors: Carpenter, Kenneth
Bibcode: 1990hst..prop.4251C
Altcode:
  This proposal represents a two pronged attack aimed at understanding the
  detailed chracteristics of red giant winds in binary star systems. Red
  giant winds can provide the most massive, sustained form of mass
  transfer in binaries. The symbiotic and related stars, which contain
  red giant and hot companion stars, permit line of sight studies through
  a range of red giant atmospheric heights. The goal of this work is to
  attempt to define both the mechanism of rapid mass loss in red giant
  stars and the details of mass transfer to the companion stars. Such
  results can provide important constraints for both stellar and binary
  evolution theories. In each case we expect to derive density and
  temperature values for the red giant wind region and compare this to the
  present understanding of single star conditions where low temperature,
  dust and molecule forming, circumstellar envelopes prevail. (Only EG
  And observations are included in this file)

Title: Winds and Chromospheres of Cool Luminous Stars -- Cycle 1
Authors: Carpenter, Kenneth
Bibcode: 1990hst..prop.3212C
Altcode:
  The goals of this program are to determine the physical characteristics
  of the winds/chromospheres around cool luminous stars. GHRS observations
  of the C II (UV 1) 1335 A and (UV 0.01) 2325 A multiplets will be
  used along with observations of the C I lines near 1655 and 1994 A to
  constrain the temperatures and densities in model chromospheres. The
  C II (UV 0.01) lines will also be used to estimate the turbulence
  in these chromospheres. The (confusing) far UV spectrum of the M
  supergiants will be explored with the GHRS. GHRS observations of Fe
  II lines will be used to study the dependence of the wind velocity
  on radial distance above the photosphere. High quality Fe II and Mg
  II profiles will be acquired to search for discrete velocity features
  and the presence of circumstellar absorption within the profiles. The
  photospheric absorption-line spectrum (2579-2675 A) of Arcturus will
  be observed in the echelle mode. Medium resolution observations of
  Fe II and Mg II in the dusty, very luminous star Mu Cep will provide
  information on the effect of dust and very low gravity on the wind
  velocity field. *** this file contains the Cycle 1 observations only ***

Title: The First GHRS Spectra of a Cool Star: The Chromosphere of
    Alpha Tau
Authors: Carpenter, K.; Robinson, R.; Ebbets, D.; Linsky, J.; Walter,
   F.; Wahlgren, G.; Ake, T.
Bibcode: 1990BAAS...22.1277C
Altcode:
  No abstract at ADS

Title: On the disappearance of OI in some high-luminosity cool stars
Authors: Carpenter, K. G.; Norman, D.; Robinson, R.;
   Fernandez-Villacanas, J. L.; Jordan, C.; Judge, P.
Bibcode: 1990ESASP.310..307C
Altcode: 1990eaia.conf..307C
  No abstract at ADS

Title: Toward Mapping the Ultraviolet Circumstellar Shells of
    Late-Type Stars
Authors: Stencel, Robert E.; Judge, Philip G.; Carpenter, Kenneth G.
Bibcode: 1990ASPC....9..467S
Altcode: 1990csss....6..467S
  Detection of spatially resolved circumstellar matter surrounding
  selected cool stars, using off-source observations made with the
  International Ultraviolet Explorer satellite, is reported. The data
  demonstrate that: (1) the instrumental scattered light profile of
  IUE appears to depend on the ultraviolet color temperature of the
  star observed, and (2) certain red stars show signal in excess of the
  instrumental levels, at spatial offsets of 10 to 20 arc-seconds from
  the star.

Title: Modeling the Ultraviolet Photospheric Spectrum of Cool Giant
    Stars - Part Two - Gamma-Crucis
Authors: Wahlgren, G. M.; Carpenter, K. G.
Bibcode: 1990ASPC....9...67W
Altcode: 1990csss....6...67W
  No abstract at ADS

Title: Modeling the ultraviolet photospheric spectrum of cool giant
    stars. II. Gamma Crucis.
Authors: Wahlgren, G. M.; Carpenter, K. G.
Bibcode: 1990ASPC....9...65W
Altcode:
  The authors present here some results of modeling the spectrum of the
  M-giant star γ Cru using similar techniques as those in their study
  of Arcturus (Carpenter and Wahlgren, 1990 - see Abstr. 52.114.89).

Title: Modeling the Ultraviolet Photospheric Spectrum of Cool Giant
    Stars - Part One - Arcturus
Authors: Carpenter, Kenneth G.; Wahlgren, Glenn M.
Bibcode: 1990ASPC....9...64C
Altcode: 1990csss....6...64C
  The UV photospheric spectra of cool giants are modeled analytically
  to facilitate the identification of UV spectral features and
  aid in the measurement of actual chromospheric flux at different
  wavelengths. Atomic line data derived experimentally and semiempirically
  are used with LTE model atmospheres by means of the SYNTHE FORTRAN code
  to generate the synthetic spectra. Surface flux spectra are determined
  and fitted to the absorption features of observed IUE high resolution
  spectra, and the modeled results are compared to the observed spectra of
  the cool giants Arcturus and the cooler Gamma Crucis. It is shown that
  the synthetic spectra can be produced for the stars, and chromospheric
  emission lines are thought to account for significant discrepancies
  between observed and calculated values. Two new fluorescence mechanisms
  are identified by modeling the ultraviolet photospheric spectrum of
  Gamma Crucis.

Title: Modeling the UV Photospheric Spectrum of K-M Giant Stars
Authors: Carpenter, K.; Wahlgren, G.
Bibcode: 1989BAAS...21Q1112C
Altcode:
  No abstract at ADS

Title: Evidence for a Cool Wind from the K2 Dwarf in the Detached
    Binary V471 Tauri
Authors: Mullan, D. J.; Sion, E. M.; Bruhweiler, F. C.; Carpenter,
   K. G.
Bibcode: 1989ApJ...339L..33M
Altcode:
  Evidence for mass loss from the K2 dwarf in V471 Tauri is found in the
  form of discrete absorption features in lines of various elements (Mg,
  Fe, Cr, Mn) and ionization stages (Mg I, Mg II, Fe I, Fe II). Resonant
  Mg II absorption indicates a mass loss rate of at least 10 to the
  -11th solar masses per year. The wind appears to be cool (no more than
  a few times 10,000 K).

Title: Fluorescence in the Outer Atmospheres of Red Giant Stars
Authors: Carpenter, K. G.
Bibcode: 1989eprg.proc..372C
Altcode: 1989IAUCo.106..372C
  No abstract at ADS

Title: Far-UV Low Resolution Spectroscopy of High Luminosity K and
    M Stars
Authors: Carpenter, Kenneth G.
Bibcode: 1989iue..prop.3391C
Altcode:
  We propose the acquisition of SWP low resolution spectra of K - M bright
  giants and supergiants to allow us to: 1) determine the underlying
  cause of the extreme weakness of certain fluorescent features, e.g. O
  I (UV 2), in the spectrum of a minority of such stars, 2) extend our
  emission measure analysis, and thus place improved constraints on the
  distribution of the emitting chromospheric plasma with temperature
  and density, to lower gravity, cooler effective temperatures, and 3)
  estimate the mean relative intensities of the Lyman-alpha and Lyman
  Beta lines within the stellar chromospheres. Used in conjunction
  with archival data, these spectra will also allow us to determine: 4)
  the dependence of radiative loss rates from cool star chromospheres
  on Teff and luminosity, 5) whether there is a gradual shift in the
  relative importance, to the chromospheric cooling, of higher and lower
  temperature species as we go to cooler and more luminous stars, and 6)
  whether there is a general trend of increasing flux in fluorescent
  species with decreasing effective temperature and increasing
  luminosity. In addition, these now spectra will be very valuable
  in optimizing the choice of such objects to be observed at higher
  resolution and higher signal/noise with the Hubble Space Telescope.

Title: Short Timescale Variations in the Outer Atmosphere of Gamma
    Crucis
Authors: Carpenter, Kenneth G.
Bibcode: 1989iue..prop.3390C
Altcode:
  We propose the acquisition of a series of UV spectra of the M-giant
  Gamma Cru to search for short timescale (i.e. 1 - 10 day) variations in
  the chromosphere and UV spectrum of the star. Our primary probes will be
  the numerous Fe II lines seen throughout the 2200 - 3200 A region, along
  with the Mg II h and k lines and the C II (UV 0.01) intercombination
  lines. High resolution line profiles and accurate fluxes will provide
  a comprehensive probe of the state (density, temperature) and stability
  (velocity field) of the outer atmosphere. The C II lines will be used to
  monitor changes in the electron density, while the behavior of the Fe
  II and Mg II lines can be used to study changes in the velocity of the
  wind versus radius and time. The outward motion of any chromospheric
  event will be followed by examining Fe II lines of differing optical
  depths, and thus differing formation heights, in the time series. Any
  detected variations will provide valuable clues toward understanding
  the excitation mechanism(s) of individual Fe II lines, and especially
  aid our attempts to distinguish lines dominated by photo-excitation
  processes (e.g. Lyman-alpha/Fe II fluorescence) from those primarily
  excited by collisions. This latter work will support the goals of 2
  major ADP program submitted in the current proposal cycle.

Title: The winds of high luminosity late-type bright stars
Authors: Stencel, Robert E.; Carpenter, K. G.
Bibcode: 1989gsfc.reptQ....S
Altcode:
  The occurrence and characteristics of the Fe II line asymmetries
  were studied to determine the radial dependence of the wind velocity
  for each star. The dependence of the Fe II profiles on spectral type
  and luminosity class and thus the variation of the velocity fields
  with stellar type was also investigated. This allows the generality
  of the results reported for alpha Ori by Carpenter (1984b) to be
  judged. In addition, new atomic data was used along with observations
  of the C II (UV 0.01) multiplet to estimate N<SUB>e</SUB> in the
  stellar winds. Measures of relative Fe II fluxes can be used in a
  probability-of-escape model to determine the opacity and hydrogen
  column density versus height in the chromosphere of each star. Finally,
  analysis of the fluorescent Fe II lines (pumped by Ly alpha) near 2507
  A will yield estimates of the intrinsic stellar Ly alpha flux that
  cannot be measured directly because of interstellar and circumstellar
  absorption. One important goal of the effort was to acquire high
  resolution spectra of the whole 2300 to 3200 A region of 13 luminous
  K and M stars as a data base that will be enormously valuable in
  planning observations with the Hubble Space Telescope High Resolution
  Spectrograph. It is also proposed to follow up the recent discovery
  of significant variations in the Fe II chromospheric emission line
  profiles from the M-giant Gamma Cru for the purpose of determining
  the underlying cause of the variations.

Title: The Ultraviolet Spectrum of Noncoronal Late-Type Stars:
    The Gamma Crucis (M3.4 III) Reference Spectrum
Authors: Carpenter, Kenneth G.; Pesce, Joseph E.; Stencel, Robert E.;
   Brown, Alexander; Johansson, Sveneric; Wing, Robert F.
Bibcode: 1988ApJS...68..345C
Altcode:
  A guide is presented to the UV spectrum of M-type giants and supergiants
  whose outer atmospheres contain warm chromospheres but not coronae. The
  M3 giant Gamma Crucis is taken as the archetype of the cooler,
  oxygen-rich, noncoronal stars. Line identifications and integrated
  line flux measurements of the chromospheric emission features seen in
  the 1200-3200 A range of IUE high-resolution spectra are presented. The
  major fluorescence processes operating in the outer atmosphere of Gamma
  Crucis, including eight previously unknown pumping processes and 21
  new fluorescent line products, are summarized, and the enhancements
  of selected line strengths by 'line leakage' is discussed. A set of
  absorption features toward the longer wavelength end of this range
  is identified which can be used to characterize the radial velocity
  of the stellar photospheres. The applicability of the results to the
  spectra of noncoronal stars with different effective temperatures and
  gravities is discussed.

Title: V471 Tauri
Authors: Sion, E. M.; Bruhweiler, F. C.; Carpenter, K.; Mullan, D. J.
Bibcode: 1988IAUC.4667....2S
Altcode: 1988IAUC.4667....0S
  E. M. Sion, Villanova University; F. C. Bruhweiler, Catholic
  University of America; K. Carpenter, Goddard Space Flight Center,
  NASA; and D. J. Mullan, Bartol Research Institute, report: "IUE
  High-Resolution SWP and LWP spectra of the Hyades member V471 Tau
  (an eclipsing-spectroscopic, pre-cataclysmic, close binary having
  spectral types K2 V + DA2) reveal very-high-velocity, cool, expanding
  gas (Fe II, Si II, C II, Mg II, O I), along the line-of-sight to the
  binary system, with an expansion velocity of -1200 km/s. There is no
  variation of the co-added absorption feature with orbital phase and
  its equivalent width is 0.035 nm, with FWHM = 30 km/s. The absorption
  appears in seven lines of the Fe II uv1 multiplet (258.5-261.7 nm),
  co-added in velocity space for each of the 11 LWP images around the
  orbit, in co-added LWP velocity plots of Mg II, Mn II, and Cr II,
  as well as in SWP plots of C II (133.5 nm), Si II (126.0 nm), and O I
  (130.2 nm), co-added in velocity space. This feature very likely has an
  origin distinct from the persistent lower velocity (-500, -260 km/s)
  absorption components of the K2 V stellar wind discovered by Mullan
  et al. (1988, ESA SP-281, p. 378; Ap.J. Letters, submitted) and from
  the narrow co-added feature of C II, Si II, and O I, at -590 km/s
  discovered by Bruhweiler and Sion (1986, Ap.J. 202, L45). The large
  expansion velocity suggests the possibility of its association with an
  ancient nova outburst. Further observations in other wavelength regions,
  including deep CCD imaging and direct photography, are strongly urged."

Title: Detection of a Cool Wind From the K Dwarf in V471 Tauri
Authors: Mullan, D. J.; Sion, E. M.; Bruhweiler, F.; Carpenter, K.
Bibcode: 1988BAAS...20..997M
Altcode:
  No abstract at ADS

Title: The Far-UV Spectrum of K and M Supergiant Stars
Authors: Carpenter, K. G.
Bibcode: 1988BAAS...20..995C
Altcode:
  No abstract at ADS

Title: V471 Tauri: The Oldest and Nearest Old Nova?
Authors: Sion, E. M.; Bruhweiler, F. C.; Carpenter, K.; Mullan, D. J.
Bibcode: 1988BAAS...20S1021S
Altcode:
  No abstract at ADS

Title: What does C II lambda 2355 A emission tell us about
    chromospheres of red supergiants ? A critical test using dzeta
    Aurigae-type K supergiants.
Authors: Schroeder, K. -P.; Reimers, D.; Carpenter, K. G.; Brown, A.
Bibcode: 1988A&A...202..136S
Altcode:
  Line fluxes and intensity ratios of the C II UV 0.01 intercombination
  multiplet near λ2325 Å have been used by Carpenter et al. (1985)
  to determine the density and the geometric extent of red giant
  chromospheres. Here the authors test the limitations of the C II method
  and the validity of the assumptions inherent in the method by means of
  observations of C II 2325 Å emission of two stars (K type supergiants
  ζ Aurigae, 32 Cygni) for which spatially resolved, empirical model
  chromospheres has been derived earlier from high resolution IUE
  observations at chromospheric eclipse phases (Schröder, 1985).

Title: Fluorescence processes and line identifications in the UV
    spectra of cool stars (Contributed paper)
Authors: Carpenter, Kenneth G.; Johansson, Sveneric
Bibcode: 1988ESASP.281a.349C
Altcode: 1988uvai....1..349C; 1988duvb.conf..349C
  Fluorescence processes active in the outer atmospheres of noncoronal
  cool stars and the UV lines they produce are summarized. Eight
  pumping processes and 21 fluorescent line products are discussed. The
  processes, which produce 12 lines, involves energy levels not previously
  known to be radiatively populated. Four of these are examples of
  self-fluorescence, whereby one or more lines of Fe II photo-excite
  through coincident lines the upper levels of other Fe II lines lines
  seen in emission, while two others explain the selective excitation
  of solitary Ni II and Si I lines. Nine of the line products are decays
  from levels in Fe I and Fe II already known to be radiatively populated.

Title: Identification of new fluorescence processes in the UV spectra
    of cool stars from new energy levels of FeII and CrII
Authors: Johansson, Sveneric; Carpenter, Kenneth G.
Bibcode: 1988ESASP.281a.361J
Altcode: 1988IUE88...1..361J; 1988uvai....1..361J
  Two fluorescence processes operating in atmospheres of cool stars,
  symbiotic stars, and the Sun are presented. Two emission lines, at
  1347.03 and 1360.17 A, are identified as fluorescence lines of Cr
  II and Fe II. The lines are due to transitions from highly excited
  levels, which are populated radiatively by the hydrogen Lyman alpha
  line due to accidental wavelength coincidences. Three energy levels,
  one in Cr II and two in Fe II, are reported.

Title: Direct UV observations of the circumstellar envelope of
    alpha Orionis.
Authors: Stencel, R. E.; Carpenter, K. G.; Pesce, J. E.; Skinner,
   S.; Brown, A.; Judge, P.
Bibcode: 1988ESASP.281a.249S
Altcode: 1988uvai....1..249S; 1988IUE88...1..249S
  Observations were made in the IUE LWP camera, low dispersion mode, with
  alpha Ori being offset various distances from the center of the Long
  Wavelength Large Aperture along its major axis. Signal was acquired
  at all offset positions and is comprised of unequal components of
  background/dark counts, telescope-scattered light, and scattered light
  emanating from the extended circumstellar shell. The star is known from
  optical and infrared observations to possess an extended, arc-minute
  sized, shell of cool material. Attempts to observe this shell with the
  IUE are described, although the deconvolution of the stellar signal
  from the telescope scattered light requires further calibration effort.

Title: The Goddard High Resolution Spectrograph for the Hubble Space
Telescope: Pre-Launch Status
Authors: Brandt, J.; Ebbets, D.; Carpenter, K.; Heap, S.
Bibcode: 1988BAAS...20..677B
Altcode:
  No abstract at ADS

Title: Space telescope and the Fe II problem
Authors: Carpenter, Kenneth G.
Bibcode: 1988ASSL..138..323C
Altcode: 1988IAUCo..94..323C; 1988pffl.proc..323C
  The capabilities of the Hubble Space Telescope, especially as they
  apply to the "Fe II problem" are reviewed. The major spectroscopic
  observing modes of both the Faint Object Spectrograph and the High
  Resolution Spectrograph are discussed and compared with those of
  the IUE satellite, with a detailed illustrative look at the options
  available for observations of Fe II (UV 1) near 2600 Å. Finally, the
  major impacts to be expected on astrophysical investigations of Fe II
  from the Space Telescope and associated instrumentation are summarized.

Title: Dinosaur Bone Beds and Mass Mortality: Implications for the
    K-T Extinction
Authors: Carpenter, K.
Bibcode: 1988LPICo.673...24C
Altcode:
  No abstract at ADS

Title: Far-UV Low Resolution Spectroscopy of M Supergiants
Authors: Carpenter, Kenneth G.
Bibcode: 1988iue..prop.3079C
Altcode:
  We propose the acquisition of SWP low resolution spectra of two M
  supergiants. Our emission measure analysis which derive approximate
  structure models of the outer atmospheric layers will be extended
  to lower gravity, cooler effective temperatures with these data. In
  combination with archive data, these spectra will be used to determine:
  1) the dependence of radiative loss rates from cool star chromospheres
  on Teff and luminosity, 2) whether there is a gradual shift in the
  relative importance, to the chromospheric cooling, of higher and
  lower temperature species as we go to cooler and more luminous stars,
  3) whether there is a general trend of increasing flux in fluorescent
  species with decreasing effective temperature and increasing luminosity
  and 4) whether the weakness of specific fluorescent lines in Alpha
  Ori is a general characteristic of M supergiants or is unique to Alpha
  Ori. In addition, these new spectra will be very valuable in optimizing
  the choice of such objects to be observed at higher resolution and
  higher signal/noise with the Hubble Space Telescope.

Title: Fe II emission line profiles in the ultraviolet spectrum of
    cool, luminous stars
Authors: Carpenter, Kenneth G.
Bibcode: 1988ASSL..138...95C
Altcode: 1988IAUCo..94...95C; 1988pffl.proc...95C
  The differences between the outer atmospheres of the coronal and
  noncoronal cool stars and the importance of massive stellar winds to the
  latter group are summarized. The utility of Fe II as a probe of such
  winds is indicated and a brief review of previous observations of Fe
  II in these stars is given. The early results of a current IUE program
  to study the chromospheres and winds of the noncoronal, late-type stars
  are presented, including evidence of a strong dependence of the mid-UV
  Fe II profiles on stellar luminosity. In addition, the dependence of
  the Fe II profiles on intrinsic line strength in spectra of Alpha Ori
  and the discovery of a variation of the Fe II profiles with time in
  spectra of Gamma Cru are discussed.

Title: Emission Line Variations in the UV Spectrum of Gacrux
Authors: Carpenter, K. G.
Bibcode: 1987BAAS...19.1026C
Altcode:
  No abstract at ADS

Title: Observaciones con IUE e IRAS de gigantes y supergigantes rojas.
Authors: Hagen, W.; Carpenter, K. G.; Stencel, R. E.
Bibcode: 1987RMxAA..14..380H
Altcode:
  . Previous observations of M giants and supergiants have indicated
  that chromospheric Ca II,H and K emission is lacking in stars with high
  circumstellar dust-to-gas ratios (Hagen, Stencel, and Dickinson 1983,
  Ap. J., 274, 286). Observations with lUE detected other chromospheric
  lines (e.g., Mg II, Al II, Fe II) in stars without Ca II emission,
  indicating that the dust does not completely quench the . However,
  line intensities in dusty stars were reduced. (Carpenter, Stencel, and
  Hagen 1986, Ap. J., 308, 859). IRAS observations of visually bright
  M giants and supergiants and simple dust shell models indicate that
  the 60 and lO0 m excesses can be satisfactorily explained by silicate
  grains. Examination of individual IRAS scans indicates spatially
  extended emission for the stars R Dor,aOri, W Hya, a Sco, AH Sco, R
  Lyr, Cep, PZ Cas and L2 Pup at 60 m. Kay : STARS-CIRCUMSTELLAR SHELLS
  - STARS-CHROMOSPHERES

Title: The Goddard High Resolution Spectrograph for the Hubble Space
    Telescope Status June 1987
Authors: Brandt, J.; Heap, S.; Carpenter, K.; Ebbets, D.; Lindler, D.
Bibcode: 1987BAAS...19..757B
Altcode:
  No abstract at ADS

Title: A Roadmap to the Ultraviolet Spectrum of Cool, Non-Coronal
    Stars
Authors: Carpenter, K. G.; Peace, J.; Stencel, R. E.; Brown, A.
Bibcode: 1987BAAS...19..705C
Altcode:
  No abstract at ADS

Title: 119 Tau
Authors: Carpenter, Kenneth
Bibcode: 1987iue..prop.2919C
Altcode:
  No abstract at ADS

Title: Variations in the Chromosphere and Stellar Wind of Gamma Crucis
Authors: Carpenter, Kenneth G.
Bibcode: 1987iue..prop.2752C
Altcode:
  We propose to follow up the recent discovery of significant variations
  in the Fe II chromospheric emission line profiles from the M-giant
  Gamma Cru for the purpose of determining the underlying cause of the
  variations. The star will be observed at five different times during
  the year with SWP low resolution and LWPHI and LWPLO resolution to
  determine whether the apparent increase in the opacity of the stellar
  wind and chromosphere is: 1) due to additional mass being added to the
  outer atmosphere through a one-time ejection of mass or an increase
  in the mass loss rate, or 2) due to a temporary or permanent increase
  in the chromospheric heating rate, or 3) is a periodic effect due,
  for example, to rotation and the resulting variable visibility of
  inhomogeneities in the chromosphere. This star is the first single,
  non-Mira M-giant for which there is clear evidence from UV lines of
  substantial chromospheric variation. It is important that we monitor
  the development of this event and attempt to understand its origin,
  while the capabilities of IUE are still available to us.

Title: Mg II Emission Lines in the Spectra of Cool, High Luminosity
    Stars
Authors: Carpenter, Kenneth G.; Stencel, Robert E.; Pesce, Joseph E.
Bibcode: 1987LNP...291..164C
Altcode: 1987LNP87.291..164C; 1987csss....5..164C
  We present the initial results of a survey of the Mg II emission
  lines in the spectra of K and M giants, bright giants, and
  supergiants. Profiles of the Mg II h and k lines in 12 such stars are
  shown in a relative spectral type/luminosity class grid. Plots based
  on the h-line data illustrate the existence of a Wilson-Bappu. effect
  in these lines and of a slight dependence of the line asymmetry on V-R
  color. A time series of Mg II profiles for the M3 giant Gamma Cru show
  that the Mg II profiles have not undergone the profile shape changes
  seen in the Fe II lines from this star over the same time period.

Title: Corrected observed stellar Lyman Alpha profiles for the
    effects of interstellar absorption and geocoronal emission
Authors: Neff, J. E.; Linsky, J. L.; Landsman, W. B.; Carpenter, K. G.
Bibcode: 1986ESASP.263..669N
Altcode: 1986NIA86......669N; 1986niia.conf..669N
  Techniques to compensate for interstellar absorption and geocoronal
  emission in IUE studies of late stars atmospheres were developed. Thus
  it is possible to determine the Lyman alpha flux from nearby cool stars
  using the low-resolution spectra in the IUE archives. The accuracy of
  such a procedure depends fundamentally upon the assumptions regarding
  the shape of the intrinsic profile and the density and velocity
  structure of the local interstellar medium, not upon measurement
  uncertainties of the low-resolution spectra. Geocoronal emission
  and saturated spectra are fatal only to a one-dimensional spectral
  analysis. When both the spatial and the spectral dimensions are
  considered, the observed Lyman alpha flux can be recovered.

Title: Current Status of the High Resolution Spectrograph (HRS)
    for the Hubble Space Telescope
Authors: Brandt, J. C.; Carpenter, K. G.; Ebbets, D.; Garner, H.;
   Heap, S.; Lindler, D.
Bibcode: 1986BAAS...18..940B
Altcode:
  No abstract at ADS

Title: Thermal Vacuum Test Results for the Hubble Space Telescope
High Resolution Spectrograph: II. Scientific Performance
Authors: Ebbets, D.; Garner, H.; Carpenter, K. G.; Brandt, J. C.;
   Heap, S.; Lindler, D.
Bibcode: 1986BAAS...18..940E
Altcode:
  No abstract at ADS

Title: Ultraviolet and Infrared Observations of Stars with
    ``Quenched'' Chromospheres and the Nature of Mass Loss
Authors: Stencel, R. E.; Carpenter, K. G.; Hagen, W.
Bibcode: 1986ApJ...308..859S
Altcode:
  Previous observational evidence implies that the presence of Ca II
  emission, a chromospheric indicator, is correlated with the gas/dust
  ratio in the envelopes of red giant and supergiant stars. An attempt
  is made to determine whether this correlation can be generalized to
  all chromospheric activity indicators and the gas/dust ratio. New
  ultraviolet observations address the strength of UV emission features
  and the fraction of the total chromospheric flux emitted in various
  lines. Evidence is found that chromospheres are not completely quenched
  in the presence of dust, but that significant alteration of relative
  radiative loss patterns may occur. These observations are interpreted
  in terms of an instability that converts warm, chromospheric gas into
  near-surface dust grains and cool gas capable of supporting molecular
  masing. This supports the dust-driven mass loss scenario for red
  giant winds.

Title: Thermal Vacuum Test Results for the Hubble Space Telescope
High Resolution Spectrograph: I. UV Optical Throughput
Authors: Carpenter, K. G.; Ebbets, D.; Garner, H.; Heap, S.; Lindler,
   D.; Brandt, J. C.
Bibcode: 1986BAAS...18..940C
Altcode:
  No abstract at ADS

Title: Mg II Emission Line Variability of Hybrid Chromosphere Stars
Authors: Brown, A.; Linsky, J. L.; Drake, S. A.; Carpenter, K. G.
Bibcode: 1986BAAS...18S.983B
Altcode:
  No abstract at ADS

Title: FeII emission line profiles in spectra of high luminosity,
    non-coronal stars
Authors: Carpenter, K. G.
Bibcode: 1986ESASP.263...99C
Altcode: 1986NIA86.......99C; 1986niia.conf...99C
  The results of a program to study the winds of noncoronal late-type
  giant and supergiant stars with IUE are presented. The primary data for
  this study are profiles, fluxes, and velocities of the Fe II emission
  lines which occur throughout the 2200 to 3230 A region of the IUE long
  wavelength spectrographs. The apparent dependence of the Fe II profiles
  on stellar luminosity (surface gravity) and intrinsic line strength is
  discussed. The discovery of significant changes in the Fe II profiles
  in spectra of Gamma Crucis (M3 III), during the period 1978 to 1985,
  that suggest a substantial change in its outer atmosphere is noted.

Title: An IUE High-Dispersion Cool-Star Atlas
Authors: Ayres, T. R.; Brugel, E. W.; Linskyl, J. L.; Brown, A.;
   Carpenter, K. G.
Bibcode: 1986LNP...254..106A
Altcode: 1986csss....4..106A
  We are planning to compile a spectral atlas based on high-dispersion
  images of representative late-type stars recorded by the International
  Ultraviolet Explorer. We solicit advice from the ultraviolet community
  concerning how best to present the spectral material.

Title: Gamma Crucis
Authors: Carpenter, Kenneth
Bibcode: 1986iue..prop.2633C
Altcode:
  No abstract at ADS

Title: Optical, UV and Radio Observations of RS Canum Venaticorum
Authors: Catalano, S.; Rodono, M.; Linsky, J. F.; Carpenter, K.;
   Gibson, D.; Gary, D.; Butler, J.
Bibcode: 1986LNP...254..253C
Altcode: 1986csss....4..253C
  No abstract at ADS

Title: IUE and IRAS observations of luminous M stars with varying
    gas-to-dust ratios.
Authors: Hagen, W.; Carpenter, K. G.; Stencel, R. E.
Bibcode: 1986NASCP2403A...8H
Altcode:
  No abstract at ADS

Title: The Winds of High Luminosity K and M Stars
Authors: Carpenter, Kenneth G.
Bibcode: 1986iue..prop.2426C
Altcode:
  The winds of high luminosity K and M stars likely play a major role
  in stellar evolution, yet this region of the H-R diagram is one of
  the least-studied with IUE, due to the very limited number of targets
  that are bright in the ultraviolet. However, high-resolution spectra
  of the long wavelength region of the few well-observed stars reveal
  extremely interesting spectra containing dozens of broad, frequently
  self-reversed and asymmetric Fe II emission lines in addition to the
  Mg II, Al II, and C II lines seen in all late-type stars. We propose a
  comprehensive study of a sample of 13 such stars using both archive and
  new observations. We shall study the occurrence and characteristics of
  the Fe II line asymmetries to determine the radial dependence of the
  wind velocity for each star. We shall also investigate the dependence
  of the Fe II profiles on spectral type and luminosity class and thus
  the variation of the velocity fields with stellar type. This will
  allow us to judge the generality of the results reported for alpha
  Ori by Carpenter (1984b). In addition, we shall use new atomic data
  along with observations of the C II(UV 0.01) multiplet to estimate Ne
  in the stellar winds. Measures of relative Fe II fluxes will be used
  in a probability-of-escape model to determine the opacity and hydrogen
  column density versus height in the chromosphere of each star. Finally,
  analysis of the fluorescent Fe II lines (pumped by Ly-alpha) near
  2507 will yield estimates of the intrinsic stellar Ly-alpha flux that
  cannot be measured directly because of interstellar and circumstellar
  absorption. One important goal of this proposal is to acquire high
  resolution spectra of the whole 2300-3200 A region of 13 luminous K and
  M stars as a data base that will be enormously valuable in planning
  observations with the Space Telescope High Resolution Spectrograph,
  which will be able to observe only small portions of the spectrum at
  one time with high sensitivity.

Title: Efficiency functions for a 316 g/mm echelle grating.
Authors: Cushman, G. W.; Carpenter, K. G.
Bibcode: 1986SPIE..627..395C
Altcode:
  The radiometric response function of the High Resolution Spectrograph
  (HRS) for the Hubble Space Telescope was measured in 1984. From the
  system efficiency measurements made in the HRS echelle modes, the
  relative efficiencies ('ripple' functions) of 14 HRS echelle orders
  have been deduced. The results agree well with a theoretical model
  of echelle efficiency, except for a residual shift of apparent blaze
  angle with spectral order. The discrepancy between nominal and fitted
  blaze angle decreases with increasing order number.

Title: The Effect of Dust on the Chromospheres of Cool, Luminous Stars
Authors: Carpenter, K. G.; Stencel, R. E.; Hagen, W.
Bibcode: 1985BAAS...17..876C
Altcode:
  No abstract at ADS

Title: Hydrogen Lyman Alpha Fluxes for Late-Type Dwarf Stars
Authors: Neff, J. E.; Carpenter, K. G.; Ayres, T. R.
Bibcode: 1985BAAS...17..879N
Altcode:
  No abstract at ADS

Title: Densities, Temperatures and Geometric Extents of C II Emitting
    Regions in the Winds of Luminous, Late-Type Stars
Authors: Carpenter, K. G.; Brown, A.; Stencel, R. E.
Bibcode: 1985mlrg.proc...55C
Altcode:
  The authors summarize techniques for using IUE observations of the
  C II UV 0.01 and UV 1 emission line multiplets at 2325 Å and 1335
  Å to estimate the electron density (N<SUB>e</SUB>) and temperature
  (T<SUB>e</SUB>) in, and the geometric extent of, the chromospheres of
  late-type stars. The results of applying these techniques to a sample
  of 15 stars observed with the IUE satellite are discussed.

Title: Emission Line Variability of RY Tau, DR Tau and SU Aur
Authors: Brown, A.; Walter, F. M.; Carpenter, K. G.; Jordan, C.;
   Judge, P.
Bibcode: 1985BAAS...17..556B
Altcode:
  No abstract at ADS

Title: Laboratory Calibration of the High Resolution Spectrograph
for Space Telescope: Absolute Sensitivity
Authors: Carpenter, K. G.; Cushman, G.; Ebbets, D.; Heap, S.;
   Brandt, J.
Bibcode: 1985BAAS...17..574C
Altcode:
  No abstract at ADS

Title: Line identifications, line strengths and continuum flux
    measurements in the ultraviolet spectrum of Arcturus.
Authors: Carpenter, K. G.; Wing, R. F.; Stencel, R. E.
Bibcode: 1985ApJS...57..405C
Altcode:
  The ultraviolet spectrum of Arcturus has been observed at high
  resolution with the IUE satellite. Line identifications, mean absolute
  'continuum' flux measurements, integrated absolute emission-line
  fluxes, and measurements of selected absorption line strengths are
  presented for the 2250-2930 A region. In the 1150-2000 A region,
  identifications are given primarily on the basis of low-resolution
  spectra. Chromospheric emission lines have been identified with
  low-excitation species including H I, C I, C II, O I, Mg I, Mg II,
  Al II, Si I, Si II, S I, and Fe II; there is no evidence for lines of
  C IV, N V, or other species requiring high temperatures. A search for
  molecular absorption features in the 2500-2930 A interval has led to
  several tentative identifications, but only OH could be established as
  definitely present. Iron lines strongly dominate the identifications
  in the 2250-2930 A region, Fe II accounting for about 86 percent
  of the emission features and Fe I for 43 percent of the identified
  absorption features.

Title: The geometric extent of C II (UV 0.01) emitting regions around
    luminous, late-type stars
Authors: Carpenter, K. G.; Brown, A.; Stencel, R. E.
Bibcode: 1985ApJ...289..676C
Altcode:
  A method is presented by which the geometric extent of the chromospheres
  around late-type stars can be estimated from measurements of the
  total emission-line flux and line ratios within the C II (UV 0.01)
  multiplet. Application of this technique to a sample of 15 late-type
  stars indicates a clear difference in the radial extent of the
  chromospheres around coronal and noncoronal stars. The former stars
  appear to have very thin chromospheres (of no more than 0.1 percent of
  the photospheric radius), while the latter stars have chromospheres
  extending, on average, out to 2.5 photospheric radii. This, in
  principle, provides information for understanding structural differences
  between late-type giant and supergiant stars with and without coronae,
  and could lead to an understanding of the mass-loss mechanisms involved.

Title: The structures and spectra of magnetic, line-blanketed model
    atmospheres
Authors: Carpenter, K. G.
Bibcode: 1985ApJ...289..660C
Altcode:
  Magnetic, line-blanketed model atmospheres for upper-main-sequence
  stars with normal elemental abundances and a slightly distorted
  dipolar magnetic field have been constructed. These were computed
  with a modified version of the Kurucz ATLAS6 model atmosphere code and
  newly computed opacity distribution functions (ODFs), which take into
  account the Zeeman splitting of the contributing atomic lines. The
  inclusion of magnetic forces changes the structure of an atmosphere
  by altering the net gravity and thus the pressure distribution in
  the upper layers of the atmosphere. These magnetic forces cause the
  structure of the stellar model to vary with latitude and to differ
  from the nonmagnetic case. The enhanced blanketing represented by the
  'magnetic' ODFS in combination with the structure changes and Zeeman
  broadening of individual lines causes the emergent spectrum to vary
  with viewing inclination and to differ from the nonmagnetic case. The
  structure and spectrum computations are described and results compared
  with those for nonmagnetic models. The results are discussed in light
  of existing observations of Ap stars, which are thought to have magnetic
  field configurations similar to the ones included in these models.

Title: The temperature of C II emission-line formation regions in
    cool stars.
Authors: Brown, A.; Carpenter, K. G.
Bibcode: 1984ApJ...287L..43B
Altcode:
  An investigation has been conducted of the temperature of C II
  emission-line formation regions in the outer atmospheres of late-type
  giant and supergiant stars. A distinct dichotomy is seen in the C II
  lambda 2325/lambda 1335 ratio between coronal and noncoronal stars. It
  is found that C II emission from noncoronal giant and supergiant stars
  comes from regions with temperatures of 7000-9000 K, with the mean
  temperature being approximately 8500 K, whereas the C II emission
  from coronal stars likely comes from hotter regions. The C II ratio
  provides a powerful empirical tool for estimating the chromospheric
  temperatures of cool giants and supergiants.

Title: Chromospheric emission lines in high-resolution LWR spectra
    (2200 - 3000 Å) of Gamma Cru (M3 III) and Alpha Ori (M2 Iab).
Authors: Carpenter, K. G.
Bibcode: 1984NASCP2349..450C
Altcode: 1984fiue.rept..450C; 1984IUE84......450C
  The identity and characteristics of the chromospheric emission
  features in the 2200 to 300 A region of high resolution spectra of
  the stars gamma Cru and alpha Ori are summarized. The velocities,
  fluxes, and asymmetries of a set of Fe II lines which share common
  upper or lower energy levels are discussed and the information gained
  from flux measurements of the C II (UV 0.01) lines is presented. The
  Fe II lines in the alpha Ori spectra indicate the general shape of
  the velocity versus radius relation in its wind. The C II (UV 0.01)
  data are combined with measures of the C II (UV 1) flux to estimate
  the electron density and temperature in the wind and the geometric
  extent of the C II emitting region in both stars.

Title: A progress report on the analysis of long exposure SWP high
    resolution spectra of cool stars.
Authors: Linsky, J. L.; Ayres, T. R.; Brown, A.; Carpenter, K.;
   Jordan, C.; Judge, P.; Gustafsson, B.; Eriksson, K.; Saxner, M.;
   Engvold, O.; Jensen, E.; Moe, O. K.; Simon, T.
Bibcode: 1984NASCP2349..445L
Altcode: 1984fiue.rept..445L; 1984IUE84......445L
  The IUE is the first experiment with sufficient sensitivity to obtain
  high resolution spectra (lambda/delta lambda is approximately 10,000)
  of many cool stars in the vitally important 1200 to 2000 A spectral
  region. These data provide qualitatively new information with
  which to understand the properties of and structures in the outer
  atmospheres of these stars. Also, these cool star spectra will be
  extremely useful in planning for the Space Telescope High Resolution
  Spectrograph, which will be 1000 times more sensitive than IUE but will
  be hampered by limited observing time and limited spectral bandwidth
  in each exposure. Very long exposure, high disperson SWP spectra of
  many stars located throughout the cool half of the HR diagram were
  obtained. These 12 to 21 hour exposures were obtained by combining
  NASA and Vilspa shifts so as to obtain the longest possible exposures
  at times of low background. Included are dwarf stars of spectral type
  G0 V to M2 V, G9.5 III to M5 II giants, G2 Ib to M2 Iab supergiants,
  a number of RS CVn-type systems, and Barium stars.

Title: Rotational velocities of later B type and A type stars as
    determined from ultraviolet versus visual line profiles.
Authors: Carpenter, K. G.; Slettebak, A.; Sonneborn, G.
Bibcode: 1984ApJ...286..741C
Altcode:
  Theoretical line profiles of the Si III 1299 and Fe II 2756 lines are
  computed for rotating B5-A7 model stars, and compared with observed
  profiles from IUE spectra to derive rotational velocities. Real
  differences in widths for ultraviolet as compared with visual line
  profiles exist in the sample of B type stars (but not for the A type
  rapidly rotating stars), although these are not as large as previously
  reported in the literature. Comparison with the theoretical line
  profiles gives rotational velocities that are in good agreement with
  visually determined v sin i values for the same stars, which suggests
  that the shape-distorted, gravity-darkened models are reasonable.

Title: Characteristics of the Fe II and C II emission in
    high-resolution IUEspectra (2300-3000 A ) of alpha Orionis.
Authors: Carpenter, K. G.
Bibcode: 1984ApJ...285..181C
Altcode:
  A study is presented of Fe II and C II emission features in the
  2300-3000 A region of four high-resolution IUE spectra of Alpha
  Ori obtained during the period 1978 April-1982 November. A set of
  42 unmutilated, unblended Fe II lines of multiplets UV 1-3, 32-33,
  35-36, and 60-64 and the C II (UV 0.01) intercombination lines have
  been identified and measured to determine their velocities, fluxes,
  and asymmetries. A correlation of Fe II line asymmetry with intrinsic
  line strength indicates a velocity field which is initially constant,
  then algebraically increases with radius to a maximum value and then
  decreases significantly before reaching an asymptotic flow speed far
  from the star. The mean velocity of the chromospheric regions emitting
  Fe II does not appear to differ substantially from the time-average
  of the photospheric velocity, but there is evidence that the two
  regions are not strongly coupled and thus that the chromosphere
  does not strictly follow the semiperiodic 6 year pulsations of the
  photosphere. An analysis of the C II line fluxes produces estimates of
  the electron density in the chromosphere in the range 3.2 x 10 to the
  7th-1.3 x 10 to the 8th per sq cm and indicates that the region emitting
  C II is geometrically thick, extending at least one-tenth, and perhaps
  as far as 1.2, photospheric radii from the base of the chromosphere.

Title: IUE and IRAS Observations of Luminous M Stars with Varying
    Gas-to-Dust Ratios
Authors: Hagen, W.; Carpenter, K. G.; Stencel, R. E.
Bibcode: 1984BAAS...16..895H
Altcode:
  No abstract at ADS

Title: Atmospheric Structures in AR Lac. I. Mapping Quiescent Features
    by Occultations &amp;Doppler Imaging
Authors: Walter, F. M.; Gibson, D. M.; Brown, A.; Carpenter, K.;
   Linsky, J. L.; Rodono, M.; Eyles, C.
Bibcode: 1984BAAS...16R.896W
Altcode: 1984BAAS...16..896W
  No abstract at ADS

Title: Book-Review - Atlas of High Resolution IUE Spectra of Late-Type
    Stars 2500-3230A
Authors: Wing, R. F.; Carpenter, K. G.; Wahlgren, G. M.
Bibcode: 1984S&T....67R.527W
Altcode:
  No abstract at ADS

Title: Ultraviolet spectroscopic observations of some Be stars of
    later typeand A-F type shell stars.
Authors: Slettebak, A.; Carpenter, K. G.
Bibcode: 1983ApJS...53..869S
Altcode:
  High-dispersion IUE spectra of 18 later type Be and A-F type shell
  stars as well as eight standard nonemission line stars have been
  analyzed for anomalous ionization and mass loss effects. It is found
  that superionization in the Be stars extends to the latest spectral
  subtypes but does not seem to be present in the A-F type stars. The
  superionized lines in the Be stars appear to be correlated with v
  sin i. Asymmetrical or violet-displaced resonance lines suggesting
  mass loss are observed in all the Be stars except one, in some of the
  standard stars, but not in the A-F stars. Lower limits to the mass
  loss rates computed from Si IV lines range between 5.3 x 10 to the
  -12th and 3.5 x 10 to the -11th solar masses/yr, with Be shell stars
  showing the largest values. Mass loss is correlated with luminosity
  and effective temperature but not with rotation.

Title: Characteristics of the Fe II and C II Chromospheric Emission
    Lines in Alpha Ori as a Function of Time
Authors: Carpenter, K. G.
Bibcode: 1983BAAS...15..966C
Altcode:
  No abstract at ADS

Title: Atlas of high resolution IUE spectra of late-type stars
    2500-3230 A
Authors: Wing, Robert F.; Carpenter, Kenneth G.; Wahlgren, Glenn M.
Bibcode: 1983ahri.book.....W
Altcode: 1983QB843.C6W56....
  No abstract at ADS

Title: Ultraviolet spectroscopic observations of some Be stars of
    later typeand A-F type shell stars.
Authors: Slettebak, A.; Carpenter, K. G.
Bibcode: 1983BeSN....8....7S
Altcode:
  No abstract at ADS

Title: Measurements of chromospheric densities and geometrical
    extensions of late-type giant and super-giant stars
Authors: Wing, R. F.; Carpenter, K. G.; Stencel, R. E.; Linsky, J. L.
Bibcode: 1983osuc.rept.....W
Altcode:
  The density sensitivity of the emission lines within the UV 0.01
  multiplet of C II near 2325 A was examined in additional late type
  giants and supergiants with deep LWR high dispersion exposures. The
  new data support the original contention based on these lines that
  noncoronal red giants possess geometrically extended chromospheres.

Title: A Study of Magnetic, Line-Blanketed Model Atmospheres.
Authors: Carpenter, K. G.
Bibcode: 1983PhDT.........2C
Altcode:
  Magnetic, line-blanketed model atmospheres for upper main-sequence
  stars with normal elemental abundances and a slightly distorted
  dipolar magnetic field have been constructed. These were computed with
  a modified version of the ATLAS6 (Kurucz, 1979) model atmosphere code
  and newly computed Opacity Distribution Functions (ODF's), which take
  into account the Zeeman Splitting of the contributing atomic lines. The
  calculation of the "magnetic" ODF's is described and the results
  are compared with the original non-magnetic Kurucz functions. The
  inclusion of magnetic forces changes the structure of an atmosphere
  by altering the net gravity and thus the pressure distribution in
  the upper layers of the atmosphere. These magnetic forces cause the
  structure of the stellar model to vary with latitude and to differ
  from the non-magnetic case. The enhanced blanketing represented by
  the "magnetic" ODF's in combination with the structure changes cause
  the emergent spectrum to vary with viewing inclination and to differ
  from the non-magnetic case. The structure and spectra computations are
  described and results compared with those for non-magnetic models. The
  results are discussed in light of existing observations of Ap stars,
  which are thought to have magnetic field configurations corresponding
  to the ones included in these models.

Title: A study of magnetic, line-blanketed model atmospheres
Authors: Carpenter, Kenneth George
Bibcode: 1983PhDT.......177C
Altcode:
  No abstract at ADS

Title: Outer atmospheres of cool stars. XII. A survey of IUE
    ultraviolet emission line spectra of cool dwarf stars.
Authors: Linsky, J. L.; Bornmann, P. L.; Carpenter, K. G.; Wing,
   R. F.; Giampapa, M. S.; Worden, S. P.; Hege, E. K.
Bibcode: 1982ApJ...260..670L
Altcode:
  Quantitative information is obtained on the chromospheres and
  transition regions of M dwarf stars, in order to determine how the outer
  atmospheres of dMe stars differ from dM stars and how they compare with
  the outer atmospheres of quiet and active G and K type dwarfs. IUE
  spectra of six dMe and four dM stars, together with ground-based
  photometry and spectroscopy of the Balmer and Ca II H and K lines,
  show no evidence of flares. It is concluded, regarding the quiescent
  behavior of these stars, that emission-line spectra resemble that of
  the sun and contain emission lines formed in regions with 4000-20,000 K
  temperatures that are presumably analogous to the solar chromosphere,
  as well as regions with temperatures of 20,000-200,000 K that are
  presumably analogous to the solar transition region. Emission-line
  surface fluxes are proportional to the emission measure over the range
  of temperatures at which the lines are formed.

Title: An Atlas of High-Resolution IUE Spectra of Late-Type Stars
Authors: Wing, R. F.; Carpenter, K. G.; Wahlgren, G. M.
Bibcode: 1982BAAS...14..918W
Altcode:
  No abstract at ADS

Title: Magnetic, Line-blanketed Model Atmospheres
Authors: Carpenter, K. G.
Bibcode: 1982BAAS...14..920C
Altcode:
  No abstract at ADS

Title: Integrated Fluxes for Emission Lines in the Ultraviolet
    Spectra of Several Planetary Nebulae
Authors: Carpenter, K. G.; Czyzak, S. J.
Bibcode: 1982Ap&SS..84..495C
Altcode:
  The IUE satellite observatory has been used to obtain
  absolutely-calibrated emission line fluxes for diagnostic lines of
  multiply-ionized C, N, O, Si, Ne, and Ar which occur in the ultraviolet
  spectral region of planetary nebulae. These data, when combined with
  data from the blue, visual, and near infrared, will provide improved
  estimates of ionic concentrations, plasma temperatures and densities,
  and elemental abundances.

Title: Fluorescence in Stellar Chromospheres
Authors: Carpenter, K. G.; Wing, R. F.; Stencel, R. E.
Bibcode: 1982BAAS...14..614C
Altcode:
  No abstract at ADS

Title: Density sensitive C II lines in cool giant stars.
Authors: Stencel, R. E.; Carpenter, K. G.
Bibcode: 1982NASCP2238..243S
Altcode: 1982NASCP2338..243S; 1982auva.nasa..243S; 1982IUE82......243S
  The density sensitivity of the emission lines within the ultraviolet
  0.01 multiplet of C II near 2325 A was examined in additional late type
  giants and supergiants with deep LWR high dispersion exposures. The
  new data support the original contention based on these lines that
  noncoronal red giants posses geometrically extended chromospheres.

Title: Integrated fluxes for emission lines in the ultraviolet
    spectra of several planetaries
Authors: Carpenter, K. G.; Czyzak, S. J.
Bibcode: 1981STIN...8213022C
Altcode:
  The IUE satellite observatory was used to obtain absolutely-calibrated
  emission line fluxes for diagnostic lines of multiply-ionized C,
  N, O, Si, Ne, and Ar which occur in the ultraviolet spectral region
  of planetary nebulae. These data, when combined with data from the
  blue, visual, and near infrared, provide improved estimates of ionic
  concentrations, plasma temperatures and densities, and elemental
  abundances.

Title: Density sensitive C II lines in cool stars of low gravity.
Authors: Stencel, R. E.; Linsky, J. L.; Brown, A.; Jordan, C.;
   Carpenter, K. G.; Wing, R. F.; Czyzak, S.
Bibcode: 1981MNRAS.196P..47S
Altcode:
  It is shown that the relative intensities of emission lines within the
  multiplet UV 0.01 of C II, around 2325 A, are sensitive to electron
  density in the range 10 to the 9th to 10 to the 7th per cu cm. The lines
  therefore offer a valuable method for measuring electron densities in
  the chromospheres of late-type giants and supergiants. Calculated line
  ratios are compared with those observed in a range of objects.

Title: Notes on the early-type components of W Cep, omicron Cet,
    CH Cyg, AR Mon, and BL Tel.
Authors: Wing, R. F.; Carpenter, K. G.
Bibcode: 1981NASCP2171..341W
Altcode: 1981uviu.nasa..341W; 1981NASCP3171..341W; 1980IUE80......341W
  Low resolution IUE spectra in both spectral regions are used to clarify
  the nature of the warmer components of several binary systems. The
  W Cep, the primary of which is a luminous K-type supergiant, shows
  an ultraviolet absorption spectrum of type B0 or B1; this system is
  heavily reddened. The hot companion of Mira (o Cet) is surprisingly
  faint in the short wavelength region, but it excites a rich emission
  spectrum from the surrounding gas. The ultraviolet active M7 giant
  CH Cyg is shown to be a binary with a hot companion. This system was
  also observed at high resolution and shows variable Fe II emission
  and well-separated circumstellar and interstellar absorptions within
  the broad Mg II emission profiles. The eclipsing binaries AR Mon and
  BL Tel are shown not to have hot companions.

Title: A Search for Technetium in Zeta Cap and Several M star Mira
    Variables
Authors: Little-Marenin, I. R.; Little, S. J.; Wing, R. F.; Carpenter,
   K. G.; Wallerstein, G.
Bibcode: 1980BAAS...12..826L
Altcode:
  No abstract at ADS

Title: Chromospheric Densities and Geometrical Extensions of Red
    Giants and Supergiants using C II Lines as Diagnostics
Authors: Stencel, R. E.; Jordan, C.; Wing, R. F.; Linsky, J. L.;
   Carpenter, K. G.; Brown, A.; Czyzak, S. J.
Bibcode: 1980BAAS...12..806S
Altcode:
  No abstract at ADS

Title: An IUE Survey of the Ultraviolet Emission Line Spectra of
    dMe and dM Stars
Authors: Carpenter, K. G.; Wing, R. F.; Bornmann, P. L.; Linsky, J. L.
Bibcode: 1980BAAS...12..538C
Altcode:
  No abstract at ADS

Title: Extension of Line Identifications in Arcturus Shortward
    to 2250A
Authors: Carpenter, K. G.; Stencel, R. E.; Wing, R. F.
Bibcode: 1980BAAS...12..529C
Altcode:
  No abstract at ADS

Title: Survey of the Ultraviolet Spectra of Late-Type Stars
Authors: Carpenter, K. G.; Wing, R. F.
Bibcode: 1979BAAS...11..419C
Altcode:
  No abstract at ADS

Title: Ultraviolet Spectra of M Stars.
Authors: Wing, R. F.; Carpenter, K. G.
Bibcode: 1978BAAS...10..444W
Altcode:
  No abstract at ADS

Title: Intercomparisons of Parallaxes from Nine Observatories.
Authors: Upgren, A. R.; Carpenter, K. G.
Bibcode: 1977BAAS....9..355U
Altcode:
  No abstract at ADS

Title: An estimate of external errors in parallaxes
Authors: Upgren, A. R.; Carpenter, K. G.
Bibcode: 1977AJ.....82..227U
Altcode:
  The estimate of the external errors in trigonometric paral1axes made
  by Hertzsprung is repeated using a nonlinear least-squares procedure
  to fit normal distributions to observed frequency distributions in
  parallaxes. The best estimate of mean error in parallax is io' 016,
  in exact agreement with Hertzsprung; but unlike him, it was made using
  only parallaxes listed in the Yale Catalogue determined at a single
  observatory. Using the entire catalogue as he did, an error of +0.018
  was found, but the smaller value is considered more realistic.

Title: Observations of the large Comet
Authors: Burder, W. C.; Stothard, J. M.; Tidmarsh, G. A.; Carpenter
Bibcode: 1861MNRAS..21..242B
Altcode:
  No abstract at ADS

