Simultaneous ultraviolet and optical observations of FK Comae.
Abstract
The authors report simultaneous photometric and spectroscopic observations of FK Comae. Photometric measurements were made in the UBVR system, and in two bands centered near Hα and Hβ, respectively. The spectroscopic measurements were obtained with the IUE satellite in the 1150 - 3200 Å band near phases 0 and 0.5, in order to distinguish between the two alternative models proposed for this class of objects: (1) single, spotted stars with active chromospheres/transition zones/coronae, (2) highly evolved binary systems in which one component has transferred almost all its mass and angular momentum to the other but still continues to feed an accretion column which generates a hot spot. The optical data show that FK Comae was in a state of low amplitude variations during the time of the IUE observations. The ultraviolet data give some indication for a phase dependence of the emission line strengths. The variations are, however, only partially consistent with the predictions of either of the two models.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- August 1985
- Bibcode:
- 1985A&A...149...41B
- Keywords:
-
- Binary Stars;
- Chromosphere;
- Optical Emission Spectroscopy;
- Stellar Activity;
- Stellar Models;
- Stellar Spectrophotometry;
- Ultraviolet Spectra;
- Variable Stars;
- Accretion Disks;
- Electron Density (Concentration);
- Emission Spectra;
- Iue;
- Light Curve;
- Starspots;
- Stellar Coronas;
- Stellar Rotation;
- Astrophysics