Mg II h and k emission from luminous M stars.
Abstract
Mg II h and k emission lines of the M2 giant beta Peg and the M5 supergiant alpha Her were detected in Copernicus observations. In the alpha Her profiles, similar to alpha Ori and alpha Sco profiles, the k line is asymmetric and the h line is symmetric. The possibility that the k line asymmetry is produced by overlying absorption is discussed. In beta Peg, both h and k lines are asymmetric, and line formation in an expanding chromosphere is indicated. The observations are in accord with one formulation of the Wilson-Bappu relation but deviate from another form of the Wilson-Bappu relation.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 1978
- DOI:
- 10.1093/mnras/183.1.17P
- Bibcode:
- 1978MNRAS.183P..17B
- Keywords:
-
- Giant Stars;
- Line Spectra;
- M Stars;
- Magnesium;
- Supergiant Stars;
- Ultraviolet Astronomy;
- Oao 3;
- Spectral Line Width;
- Stellar Atmospheres;
- Stellar Magnitude;
- Astronomy;
- Emission Lines:M Giants;
- Line Profiles:M Giants