Rotational modulation of chromospheric features in late-type stars.
Abstract
Three RS CVn-type binaries (HR 1099, II Peg, and AR Lac) and the prototype BY Dra binary system were observed by IUE at regular intervals throughout their 2.0 to 6.7 day periods. Ground based photometry and radio observations were also made. Flux variations of emission lines formed in the chromospheres and transition regions of two of these stars are discussed. The phase relationship between the photometric observations and the line variations and their relevance to the location of dark star spots are considered. The evidence suggests that in the spotted variables the fluxes of the chromospheric and transition region lines vary in a manner such that maximum line flux corresponds to optical minimum or maximum spot visibility. This is consistent with a model of a solar-like dark spot distribution on the surface of these stars.
- Publication:
-
Third European IUE Conference
- Pub Date:
- June 1982
- Bibcode:
- 1982ESASP.176..125B
- Keywords:
-
- Astrophysics;
- Binary Stars;
- Chromosphere;
- Emission Spectra;
- Late Stars;
- Line Spectra;
- Stellar Rotation;
- Iue;
- Stellar Luminosity;
- Stellar Spectrophotometry;
- Variable Stars