Coronal activity in F-, G- and K-type stars. II. Coronal structure and rotation.
Abstract
Einstein Observatory soft X-ray spectra for a sample of 34 late-type stars are analyzed in order to determine coronal temperatures and emission features per unit area at the stellar surface. No obvious relation between coronal temperature and (B-V) color index could be found. Coronal temperature is dependent on stellar luminosity class. The data are discussed in terms of a model for static magnetic loops, and indications are found for a variety of coronae in which the sizes of the dominating loops range from more compact than loops in solar-active regions to loops that are comparable to the pressure scale height (or even greater). Despite observed structural differences, a single, strict relation holds between X-ray surface flux density and the Ca II H + K excess flux density of these stars. Coronal activity and structure are noted to be related to the stellar rotation rate.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1984
- Bibcode:
- 1984A&A...138..258S
- Keywords:
-
- F Stars;
- G Stars;
- K Stars;
- Stellar Activity;
- Stellar Coronas;
- Stellar Rotation;
- X Ray Astronomy;
- Spectrum Analysis;
- Stellar Models;
- Stellar Spectra;
- Stellar Structure;
- Astrophysics