CA II and K chromospheric emission in F-and G-type stars.
Abstract
A survey of representative Ca II H and K line profiles (the most pronounced chromospheric indicators observable from the ground) is presented to illustrate the chromospheric emission of different types of F and G stars. Of the 90 stars observed, a typical one is selected for each spectral type, leaving a sample of 47. The spectral types are taken from Jaschek (1978), except when superseded by Keenan and Pitts (1980). For BS 3591 the Bright Star Catalog classification of F 8 III is retained, and data for the sun (G 2 V) refer to observations of skylight, which is almost equal to integrated sunlight. General trends in the changing appearance of chromospheric emission, as well as the physical scatter of chromospheric activity levels among stars of similar photospheric properties, are presented. It is shown that the sun's level of chromospheric activity does not deviate much from what is typical for field stars of a similar spectral class.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 1981
- Bibcode:
- 1981A&A....98..367D
- Keywords:
-
- Atmospheric Radiation;
- Calcium;
- Chromosphere;
- F Stars;
- G Stars;
- H Lines;
- K Lines;
- Spectral Line Width;
- Stellar Spectra;
- Emission Spectra;
- Stellar Radiation;
- Variable Stars;
- Astronomy