Long-term behaviour of starspots. III. Active longitudes on the long-period RS CVn star HK Lacertae.
Abstract
Thirteen years of photometry were used to study active longitudes on the surface of HK Lacertae. The decaying and forming phenomena of active areas in the years of 1980-1981, 1983-1984, and 1988-1989 are shown. New activity centers suddenly occur near the same orbital phase (0.6) and have lifetimes of several (greater than 6) years. The average rotational period of HK Lac is 24.2852 d; compared to the orbital period of 24.4284 d, this implies a 32 degree/year drift of the active areas on the stellar surface. Two possible interpretations for the period difference are discussed: pseudosynchronism and rigidity of magnetic patterns. The active longitudes on HK Lac are compared with similar phenomena found on the sun.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 1991
- Bibcode:
- 1991A&A...251..531O
- Keywords:
-
- Late Stars;
- Light Curve;
- Starspots;
- Stellar Activity;
- Astronomical Photometry;
- Longitude Measurement;
- Stellar Orbits;
- Astrophysics