Long-term monitoring of active stars. I. 1988-89 UBV photometry with the PHOENIX APT.
Abstract
As part of a large program aimed at studying the global properties and evolution of active star atmospheres, high-precision UBV photometry of selected RS CVn, BY Dra, and FK Com-type systems has been carried out since early 1988 by using the Phoenix 25-cm Automatic Photoelectric Telescope at Whipple Observatory on Mt. Hopking (USA, AZ). We present the results of systematic obsrvations of nine active stars monitored during the years 1988 and 1989. Significant evolution of the wave-like light curves for most of the observed stars, both in amplitude and shape, is found. These photometric data can give important clues on the lifetimes of spotted areas and associated magnetic structures, differential rotation and solar-like cycles, and are required to address the question of spatial and physical correlations between confined structures in active star photospheres and outer atmospheres, the latter derived from chromospheric and transition region spectral signatures at other wavelengths. Evidence of long-term variability for most of the observed stars is also presented.
- Publication:
-
Astronomy and Astrophysics Supplement Series
- Pub Date:
- October 1992
- Bibcode:
- 1992A&AS...95...55R
- Keywords:
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- Stellar Activity;
- Stellar Spectrophotometry;
- Ubv Spectra;
- Variable Stars;
- Eclipsing Binary Stars;
- Light Curve;
- Stellar Atmospheres;
- Stellar Evolution;
- Stellar Luminosity;
- Astronomy