Progress in Ultraviolet Stellar Spectrophotometry with S59
Abstract
A progress report is given of investigations related to observations of stellar spectra obtained with the ultraviolet stellar spectrophotometer S59 aboard the ESRO TD-1A satellite. We describe first the processing of the observations: intensity and wavelength calibration, identification of lines, classification of spectra. Thereafter some important groups of lines are dealt with: non-LTE computation of the Mg ii lines are presented: apart from the peculiar emission line and shell stars they compare well with the observations; intensity ratios, of Fe ii and Fe iii lines are an important temperature classification criterion. Interstellar UV lines indicate large deficiencies of some metals, as compared to solar values. A new ultraviolet continuous extinction curve is determined. We discuss the strong outstreaming motions observed in α Cygni, and the consequent mass loss of this star (< 3 × 10-10 mathfrak{M}_ odot yr-1and finally we describe the composite spectrum of the (WC8+09I) bnary γ2 Velorum; the ultraviolet continuous spectrum of the WC star is about one magnitude brighter than any theory predicts.
- Publication:
-
Astrophysics and Space Science
- Pub Date:
- December 1975
- DOI:
- 10.1007/BF00647130
- Bibcode:
- 1975Ap&SS..38..313D
- Keywords:
-
- Esa Satellites;
- Satellite-Borne Instruments;
- Stellar Spectrophotometry;
- Ultraviolet Spectra;
- Continuous Spectra;
- Interstellar Extinction;
- Satellite Observation;
- Shell Stars;
- Spaceborne Astronomy;
- Spectral Line Width;
- Astronomy