Author name code: bessey ADS astronomy entries on 2022-09-14 author:"Bessey, Robert J." ------------------------------------------------------------------------ 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 × 1010 cm−3 at observing heights of 6000km, while maximum and minimum values were ∼-1.1 × 1011 cm−3 at 6000km and ∼- 2 × 1010 cm−3 at 10000km. Electron temperatures range between 12 000 K and 16 000 K. Profile halfwidths indicate turbulent velocities of 12 to 22 km s−1, and spectral tilts are interpreted as caused by differential velocity fields of ∼-3 km s−1 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-1 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 ⊙ 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⊙. 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−1 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 × 106 K at a height of 60000 km, and a solar wind mass flux of 10-9 g cm-2 s-1. 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.