| Issue |
A&A
Volume 382, Number 3, FebruaryII 2002
|
|
|---|---|---|
| Page(s) | L9 - L12 | |
| Section | Letters | |
| DOI | https://doi.org/10.1051/0004-6361:20011295 | |
| Published online | 15 February 2002 | |
Letter to the Editor
X-ray emission from the ultracool dwarf LHS 2065
Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany e-mail: cliefke@hs.uni-hamburg.de
Corresponding author: J. H. M. M. Schmitt, jschmitt@hs.uni-hamburg.de
Received:
30
July
2001
Accepted:
15
September
2001
We report the results of a 68 ks long X-ray
observation of the M9V ultracool dwarf
star LHS 2065 with
the ROSAT high resolution imager (HRI). During the observations a major
X-ray flare occurred with a peak X-ray luminosity of
erg/s and a total soft energy release
of 
erg. In addition, another flare with smaller
peak X-ray luminosity and energy release occurred. The X-ray observations
were carried out half a year apart. In the first half of the observations
no significant X-ray emission from LHS 2065 could be detected, while in the
second half in addition to flares also quiescent X-ray emission at a level
of 
erg/s was seen. LHS 2065 belongs to the coolest
hydrogen burning stars known. The ROSAT observations show that coronal
emission may be quite common even among such very late-type stars.
Key words: stars: activity / stars: coronae / stars: late type / stars: flare / X-rays: stars
© ESO, 2002
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