ROSAT Observations of FK Comae Berenices
Abstract
We obtained ROSAT PSPC observations of FK Com over a period of 24.4 h, or 0.42 rotation. During the observations the x-ray flux increased by a factor of at least 5 before declining toward its previous level. A single temperature Raymond-Smith model is adequate to model the low signal-to-noise ratio spectrum from each observation interval. Initially the spectrum was that of a 8.5 x 106 K plasma, with L9sub x)=0.66 x 1031 erg s-1. When the x-ray flux was greatest, the model plasma temperature rose to 2.5 x 107 K, and Lx=3.46 x 1031 ergs-1. During the post-maximum decline in luminosity the plasma temperature was approximately 12 x 106 K. We conclude that the increase of x-ray flux recorded by ROSAT was due to an x-ray flare with a 1.5 h decline time scale.
- Publication:
-
The Astronomical Journal
- Pub Date:
- July 1994
- DOI:
- 10.1086/117069
- Bibcode:
- 1994AJ....108..299W
- Keywords:
-
- Astronomical Spectroscopy;
- Cometary Atmospheres;
- Stellar Luminosity;
- Stellar Rotation;
- X Ray Astronomy;
- X Ray Sources;
- Image Analysis;
- Signal To Noise Ratios;
- Temperature Dependence;
- Astrophysics;
- STARS: INDIVIDUAL: FK COMAE BERENICES;
- X-RAYS: STARS;
- STARS: FLARE