Rotational modulation and flares on RS Canum Venaticorum and BY Draconis stars. XII. Near-to-simultaneous high resolution UV and optical observations of II Pegasi during July 1984.
Abstract
Nearly simultaneous high resolution ground-based optical and IUE satellite UV spectroscopy and an optical light curve of the RS CVn star II Peg are presented. It is shown that the chromospheric and transition region radiative losses of the star in July 1984 are lower than previously recorded means. The flux in the Lyman-alpha line is estimated and evidence is given for variability in all of the emission lines. This variability appears to be correlated with the optical spots. Line profiles at two rotational phases for the principal UV emission lines show an excess broadening over and above the combined instrumental plus Doppler broadening.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- April 1989
- Bibcode:
- 1989A&A...214..227B
- Keywords:
-
- Irregular Variable Stars;
- Starspots;
- Stellar Flares;
- Stellar Rotation;
- Astronomical Spectroscopy;
- H Alpha Line;
- Lyman Alpha Radiation;
- Stellar Composition;
- Ultraviolet Spectroscopy;
- Astrophysics