An indication of extended chromospheres in Line Width-Luminosity Relations.
Abstract
Measurements of Mg II k, Ca II K, and H-alpha line widths in late-type stars are compiled together with stellar basic parameters and the net radiative losses of their chromospheres (estimated from the Mg II emission line intensities). It is found that in giants and supergiants the Mg II kl width corrected for activity and abundance difference shows a different power dependence on the stellar surface gravity from that in dwarfs. The widths of Mg II k and Ca II K lines are linearly correlated even in these giants and supergiants. These facts indicate that the extended chromosphere is a universal phenomenon in the low-gravity late-type stars.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- 1988
- Bibcode:
- 1988PASJ...40..475W
- Keywords:
-
- Chromosphere;
- Late Stars;
- Spectral Line Width;
- Stellar Luminosity;
- Stellar Spectra;
- Abundance;
- Emission Spectra;
- Radiative Transfer;
- Stellar Activity;
- Stellar Gravitation;
- Velocity Distribution;
- Astrophysics