EXOSAT observations of M dwarf stars in the solar neighborhood.

Abstract

The authors present EXOSAT observations of a sample of nearby (d < 6 pc) M dwarf stars most of which have not previously been observed in X-rays. All the target stars were detected except one (Gl 754, spectral type M7). The X-ray luminosities derived are in the typical range of M dwarf X-ray luminosities derived from Einstein Observatory data, and the authors find further evidence for a drop in X-ray luminosity towards late spectral types. The EXOSAT filter ratios indicate the presence of gas at temperatures in excess of 10⁷K, again confirming the Einstein Observatory results. The observations provide no evidence for any time variability in the form of flares or trends.