Quiescent X-ray emission from the M9 dwarf LHS 2065
Abstract
We investigate an archival XMM-Newton observation of LHS 2065, an ultracool dwarf with spectral type M9. We clearly detect LHS 2065 at soft X-ray energies in less than 1 h effective exposure time above the 3 sigma level with the PN and MOS1 detector. No flare signatures are present and we attribute the X-ray detection to quasi-quiescent activity. From the PN data we derive an X-ray luminosity of L_x = 2.2 +/- 0.7 x 10^26 erg/s in the 0.3-0.8 keV band, the corresponding activity level of log L_x/L_bol = -3.7 points to a rather active star. Indications for minor variability and possible accompanying spectral changes are present, however the short exposure time and poor data quality prevents a more detailed analysis. LHS 2065 is one of the coolest and least massive stars that emits X-rays at detectable levels in quasi-quiescence, implying the existence of a corona.
Cite
@article{arxiv.0806.3863,
title = {Quiescent X-ray emission from the M9 dwarf LHS 2065},
author = {J. Robrade and J. H. M. M. Schmitt},
journal= {arXiv preprint arXiv:0806.3863},
year = {2009}
}
Comments
accepted by A&A, 3 pages, 2 figures (research note)