Author name code: bessey
ADS astronomy entries on 2022-09-14
author:"Bessey, Robert J." 
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Title: Modelling forbidden line emission profiles from colliding
    wind binaries
Authors: Ignace, R.; Bessey, R.; Price, C. S.
Bibcode: 2009MNRAS.395..962I
Altcode: 2009arXiv0902.0527I; 2009MNRAS.tmp..422I
  This paper presents calculations for forbidden emission-line profile
  shapes arising from colliding wind binaries. The main application
  is for systems involving a Wolf-Rayet (WR) star and an OB star
  companion. The WR wind is assumed to dominate the forbidden line
  emission. The colliding wind interaction is treated as an Archimedean
  spiral with an inner boundary. Under the assumptions of the model, the
  major findings are as follows. (i) The redistribution of the WR wind as
  a result of the wind collision is not flux conservative but typically
  produces an excess of line emission; however, this excess is modest at
  around the 10 per cent level. (ii) Deviations from a flat-toped profile
  shape for a spherical wind are greatest for viewing inclinations that
  are more nearly face-on to the orbital plane. At intermediate viewing
  inclinations, profiles display only mild deviations from a flat-toped
  shape. (iii) The profile shape can be used to constrain the colliding
  wind bow shock opening angle. (iv) Structure in the line profile tends
  to be suppressed in binaries of shorter periods. (v) Obtaining data
  for multiple forbidden lines is important since different lines probe
  different characteristic radial scales. Our models are discussed in
  relation to Infrared Space Observatory data for WR 147 and γ Vel
  (WR 11). The lines for WR 147 are probably not accurate enough to
  draw firm conclusions. For γ Vel, individual line morphologies are
  broadly reproducible but not simultaneously so for the claimed wind
  and orbital parameters. Overall, the effort demonstrates how lines
  that are sensitive to the large-scale wind can help to deduce binary
  system properties and provide new tests of numerical simulations.

Title: Coronal Temperature Measurements Near a Helmet Structure Base
    at the 1973 Solar Eclipse
Authors: Bessey, R. J.; Liebenberg, D. H.
Bibcode: 1984SoPh...94..239B
Altcode:
  Observations of coronal Fe XIV emission lines from the NE quadrant
  during the 1973 solar eclipse are reported. Temperatures are deduced
  from a pure thermal broadening model, and, in the region near an
  observed white-light enhancement, an alternative interpretation of
  halfwidth as being in part due to turbulent velocities is suggested.

Title: The Formation of Prominences by Thermal Instability - a
    Numerical Study
Authors: Mason, S. F.; Bessey, R. J.
Bibcode: 1983SoPh...83..121M
Altcode:
  A two-dimensional model of prominence formation in a region
  containing a magnetic neutral sheet is constructed for a variety
  of initial conditions, assuming the coronal plasma to be described
  by the usual hydromagnetic approximation, with infinite electric
  conductivity. In each case the magnetic field is initially vertical,
  varying antisymmetrically with respect to the neutral sheet, to a
  maximum value at a distance of 70 000 km from the neutral sheet. In
  the first case, the plasma is initially in hydrostatic equilibrium,
  whereas in successive cases, the pressure is assumed to be of such
  a value that the plasma is in lateral equilibrium of total pressure
  (gas plus magnetic). In a variation of this case, the value of the
  solar gravitational field was artificially reduced, and the effects
  considered.

Title: Coronal Emission Line Profiles with Five Arc Second Spatial
    Resolution
Authors: Bessey, R.; Liebenberg, D. H.
Bibcode: 1980BAAS...12..916B
Altcode:
  No abstract at ADS

Title: Evidence for temporal variations of coronal emission line
    intensity and profile.
Authors: Liebenberg, D. H.; Bessey, R. J.; Watson, B.
Bibcode: 1976SoPh...50..109L
Altcode:
  The time sequence of line profiles of Fe XIV emission obtained at the
  1965 solar eclipse is examined for temporal variations of intensity and
  profile. Although no variations are found in some regions examined,
  two regions with intensity and profile line width variations are
  found. A simple temperature wave is consistent with observations.

Title: A time evolution study of limb spicule spectra.
Authors: Krall, K. R.; Bessey, R. J.; Beckers, J. M.
Bibcode: 1976SoPh...46...93K
Altcode:
  Time sequences of simultaneous spectra of limb spicules, obtained
  using the Sacramento Peak Observatory's tower telescope and echelle
  spectrograph are analyzed. Intensity determinations of Hα and K, H,
  λ 8498 and λ 8542 of calcium are tabulated for three observing
  heights. Electron densities averaged over the entire visible
  lifetimes of spicules are ∼-6 × 10<SUP>10</SUP> cm<SUP>−3</SUP>
  at observing heights of 6000km, while maximum and minimum values were
  ∼-1.1 × 10<SUP>11</SUP> cm<SUP>−3</SUP> at 6000km and ∼- 2 ×
  10<SUP>10</SUP> cm<SUP>−3</SUP> at 10000km. Electron temperatures
  range between 12 000 K and 16 000 K. Profile halfwidths indicate
  turbulent velocities of 12 to 22 km s<SUP>−1</SUP>, and spectral
  tilts are interpreted as caused by differential velocity fields of ∼-3
  km s<SUP>−1</SUP> per 1000 km. No large scale spicule expansions or
  contractions are observed, although possible expulsions or accretions
  of material are observed. Spicules may be wider in the calcium K and
  H lines than in Hα.

Title: Coronal Emission Line Profile Observations at Total Solar
Eclipses. II: 30 May 1965 Results, Deconvolution and Interpretation
Authors: Liebenberg, D. H.; Bessey, R. J.; Watson, B.
Bibcode: 1975SoPh...44..345L
Altcode:
  High resolution spectra of the coronal emission line Fe XIV at 530.3
  nm obtained at the 30 May 1965 total solar eclipse are analyzed and
  interpreted. Deconvolution techniques that preserve the line intensity
  vs wavelength profile shape are developed to obtain further resolution
  improvement. The west limb coronal enhancement is determined to have
  temperatures less than 3 MK and turbulent velocities of ∼25 km
  s<SUP>-1</SUP> decreasing with altitude. Temperature gradients provide
  evidence for marginal solar wind flow from this enhancement. Above the
  quiet photosphere in the southwest quadrant the comparison of line and
  continuum intensities and consideration of line width suggest to us
  the coronal region is filled with inhomogeneous plasma, dense enough
  in localized regions to maintain collisional excitation. Solar wind
  flow from this region obtains when turbulent velocities are assumed
  to contribute to the line broadening. We identify this region as a
  coronal hole and suggest that coronal material is heated by the quiet
  photosphere below.

Title: On the Spicular Density Enhancement in the Region of Formation
Authors: Sahai, S. K.; Bessey, R. J.
Bibcode: 1975SoPh...42...67S
Altcode:
  The possibility is examined of setting an upper limit to the density
  enhancement of solar spicules relative to their formation region. The
  total conductive energy per sec available in a spicular region is
  determined analytically together with the total energy radiated per
  sec and the maximum density enhancement in the same region. The results
  indicate that spicules cannot cover more than 8% of the surface in their
  formation region and that at least 13% of the downward conductive flux
  must be directed from interspicular regions to rosette centers.

Title: Solar Wind Development in the Middle Corona
Authors: Liebenberg, D. H.; Bessey, R.; Watson, B.
Bibcode: 1975BAAS....7..358L
Altcode:
  No abstract at ADS

Title: Observed coronal temperatures at 1.37R <SUB>⊙</SUB> in the
    region of a helmet structure
Authors: Liebenberg, D. H.; Bessey, R. J.; Watson, B.
Bibcode: 1975SoPh...40..387L
Altcode:
  During the total solar eclipse, 1965 May 30, a 25 cm aperturef/8.0
  telescope and Fabry-Perot interferometer were operated aboard the
  USAF-AEC aircraft. High resolution spectra of the FeXIV emission line,
  530.3 nm, were obtained. Deconvolved intensity vs wavelength profiles
  of the second order fringe overlay a helmet structure on the NM limb at
  out to 1.37R<SUB>⊙</SUB>. The profiles yield coronal temperatures,
  absolute intensities and Doppler velocities in regions of apparently
  open magnetic field structure and within the closed field lines of
  the helmet. Together with white light intensities the observations
  are interpreted to provide temperatures and turbulent velocities in
  and around this coronal structure. Comparison is made with a model by
  Billings and Roberts. We suggest a model with radial flow (solar wind)
  velocities of ∼ 60 km s<SUP>−1</SUP> satisfies the observations
  in the open field line region.

Title: A Dynamical Model of the Corona
Authors: Browne, Stephen L.; Bessey, Robert J.
Bibcode: 1973SoPh...31..351B
Altcode:
  The hydrodynamic equations for an ideal, inviscid, fully ionized
  hydrogen gas in a gravitational, but not magnetic, field are solved by
  an explicit Lax-Wendroff two-step technique using a one-dimensional
  slab symmetry. Radiation and thermal conductivity are included. The
  model spans 100000 km starting from the chromosphere-corona transition
  region. An initially isothermal gas is seen to evolve coronal
  properties in 4000 s, by which time it settles into dynamic equilibrium
  characterized by a 2000 km transition region, a temperature maximum
  of 1.6 × 10<SUP>6</SUP> K at a height of 60000 km, and a solar wind
  mass flux of 10<SUP>-9</SUP> g cm<SUP>-2</SUP> s<SUP>-1</SUP>.

Title: Coronal Emission Line Profile Analysis from Airborne Eclipse
    Observations of 30 May 1965.*
Authors: Liebenberg, D. H.; Bessey, R.; Watson, B.
Bibcode: 1973BAAS....5S.275L
Altcode:
  No abstract at ADS

Title: Thermally Driven Motions in a Gravitational Atmosphere
Authors: Bessey, R. J.; Kuperus, M.
Bibcode: 1970SoPh...12..216B
Altcode:
  Numerical solutions of the non-linear equations of fluid dynamics for a
  compressible inviscid initially isothermal atmosphere are given using
  Lax' method for the integration of the equations when discontinuities
  occur in the flow. The motion of the atmosphere is studied following
  the heating of a thin layer in the atmosphere. It is found that
  for a sufficiently large heat input the atmosphere strongly expands
  towards the regions of lower densities. In most cases a shock wave is
  formed which precedes the expanding region. The possible occurrence
  of thermally generated motions in the solar chromosphere is discussed.

Title: Thermally Driven Motions in a Gravitational Atmosphere
Authors: Bessey, R. J.; Kuperus, M.
Bibcode: 1969cctr.conf..191B
Altcode:
  No abstract at ADS

Title: Doppler Shifts and Line Broadening in Spicules.
Authors: Athay, R. Grant; Bessey, R. J.
Bibcode: 1964ApJ...140.1174A
Altcode:
  Doppler shifts measured for solar spicuies in Ha, D3, and H (Ca ii)
  suggest that the anomalously broad lines of Ca ii (Athay 1961) are due,
  in part, to inadequate spatial resolution as suggested by Zirker (1962),
  but that this is not the primary cause of the anomalous broadening. Ha
  and H and K spicules are found to have predominantly wide profiles at
  low and intermediate heights, but at great heights the profile widths
  for most of the few remaining features are only about one-third as
  wide as at lower heights. It appears that this results mainly, however,
  from the fact that the features with narrow profiles are intrinsically
  brighter at great heights than are the features with wide profiles
  It does not appear to result from strong systematic decrease of line
  width with height for individual spicules. Only a small percentage of
  the features with wide profiles resolves into clusters of spicules
  with narrow profiles at great heights. Doppler velocities are found
  to be less than 12 km/sec for about two-thirds of equatorial spicules
  with the remaining one-third showing Doppler velocities up to about 30
  km/sec. Almost all polar spicules have Doppler velocities less than 12
  km/sec. No other significant differences between polar and equatorial
  spicules were found.

