Long-term behaviour of starpots. I. Polar starspots, rotational modulation and flare activity of V 833 Tauri.
Abstract
V 833 Tau is a late-type (dK5e) single lined spectroscopic binary where the primary is much brighter than the secondary. This paper presents multicolor photometry from 1983 and 1987-1990 to study the light variability of the star. In addition, the discovery of flare activity of V 833 Tau is announced, and it is determined that 0.1 percent of the U-filter flux is due to flaring. Long-term changes on a time scale of months with amplitudes of 0.1-0.2 mag in different filters were found. The system has a low inclination (about 20 deg), so this variability may be interpreted as due to a changing polar spot area. Small amplitude (0.04 mag) periodic variations were discovered in 1983, presumably caused by lower latitude spots rotating in and out of view. Superimposed on the longterm variability, such rotational modulation was also detected in 1989 and 1990, when the polar spot had a reduced size (i.e. during bright star intervals). The observed magnitude ranges fit the long-term trend found by Hartmann et al. (1981). The rotational period of the star is about 1.79 days.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1991
- Bibcode:
- 1991A&A...242..443O
- Keywords:
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- Binary Stars;
- K Stars;
- Starspots;
- Stellar Flares;
- Stellar Rotation;
- Stellar Magnitude;
- Stellar Spectrophotometry;
- Ubv Spectra;
- Astrophysics