Variable X-ray emission from the dMe star EXO 040830-7134.7.
Abstract
The serendipitous X-ray source EXO 040830-7134.7 is identified with a m(v) = 12.5 dMe star. A total of 30 observations of this source were made with the Exosat low energy telescope during an interval of two years, representing the most complete long term coverage of X-ray emission from a single dMe star. In the usually observed quiescent state, the X-ray luminosity of EXO 040830-7134.7 can be described by a normal distribution with a standard deviation of 0.4 times the average value. During two observations, the source was almost a factor 3 brighter than average. Additionally, during one observation, the source was detected to be a factor 7 brighter than average for at least two hours. If this increase is due to a stellar flare, then both the totally emitted flux and typical recurrence time of the flare indicate that it is quite unlike strong X-ray flares observed in dMe flare stars so far.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- August 1989
- Bibcode:
- 1989A&A...220..221V
- Keywords:
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- Flare Stars;
- Stellar Coronas;
- X Ray Stars;
- Luminosity;
- Standard Deviation;
- Stellar Flares;
- Variability;
- Astrophysics