The origin of low-velocity absorption components in the MG II resonance lines of hybrid-chromosphere stars.
Abstract
It is argued that the low-velocity absorption features seen in the Mg II resonance lines of seven confirmed and three probable hybrid-chromosphere stars are interstellar rather than circumstellar in origin. From a comparison of radial velocities based on all available spectra in the International Ultraviolet Explorer (IUE) archives with estimates of the interstellar velocity along each line of sight, a good correlation between the observed position of the low-velocity component and the predicted interstellar feature is found. It is also shown that previous arguments in favor of the circumstellar origin of the low-velocity absorption features are either incorrect or implausible. The conclusion of the present study may modify previously proposed models of hybrid star winds which have assumed a priori that both Mg II absorption components are circumstellar.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 1984
- DOI:
- 10.1086/162459
- Bibcode:
- 1984ApJ...284..774D
- Keywords:
-
- Absorption Spectra;
- Chromosphere;
- Interstellar Matter;
- Late Stars;
- Metallic Stars;
- Resonance Lines;
- Iue;
- Magnesium;
- Radial Velocity;
- Stellar Atmospheres;
- Stellar Envelopes;
- Stellar Winds;
- Ultraviolet Spectra;
- Astrophysics