Photospheric activity of HD 220140, the optical counterpart of the X-ray source H 2311+77.
Abstract
We present and discuss the photoelectric observations of HD 220140 obtained at Merate Observatory and compare them with the ones obtained by Bianchi et al. (1991). The star shows a variable light activity with a fundamental period of 2.766 d. At the epoch of our observations the light curve was double-wave shaped, while at the epoch of the Bianchi et al. (1991) data it was essentially a single wave. The light curve variability as well as the changing mean brightness of the star observed in our data can be explained by the rotation of a star with at least two groups of photospheric dark spots, whose extent and/or location is changing with characteristic time-scales of a few rotational cycles.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 1992
- Bibcode:
- 1992A&A...256..459M
- Keywords:
-
- Photosphere;
- Stellar Atmospheres;
- Variable Stars;
- X Ray Sources;
- Astronomical Observatories;
- Light Curve;
- Starspots;
- Stellar Luminosity;
- Stellar Rotation;
- Astrophysics