An X-ray survey of short period low-mass eclipsing binary systems

Lowmass eclipsing binaries serve as a benchmark for stellar evolution models asthey currently present the only means of acquiring stellar radii and masses witha sufficiently high degree of precision. Somewhat surprisingly one findsdiscrepancies between observed and modelled radii, which may be related to theactivity of the systems. We propose to carry out short, exploratory XMMNewtonobservations of five of the systems where the discrepancies between predictionand observation are largest.