EXOSAT detection of an X-ray flare from the solar type star pi 1 UMa.
Abstract
An X-ray flare has been detected on the G0 dwarf star π1UMa using the European satellite EXOSAT. With the exception of the Sun, this is the first time that an X-ray flare has been observed in a normal solar-type star, which is not a member of a binary system and is not a classical flare star. As a member of the Ursa Major Cluster, π1UMa is a young, rapidly rotating star with a high level of chromospheric and coronal activity. The energy emitted in X-rays by the observed flare is at least one order of magnitude higher than the total energy released in large solar flares. The authors interpret the event as occurring in one or more magnetic loops which occupy only a small fraction of the star surface. The flare is found to cool both by radiation and conduction. The authors derive physical parameters for the emitting region and compare them with transient events occurring on the Sun, on dMe flare stars and on RS CVn and Algol-type binaries.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 1986
- Bibcode:
- 1986A&A...157..217L
- Keywords:
-
- Dwarf Stars;
- Spaceborne Astronomy;
- Stellar Flares;
- X Ray Sources;
- Exosat Satellite;
- X Ray Astronomy;
- Solar Physics