092392

Magnetic activity features are often variable and some systems show clearsinusoidal modulations. Such activity cycles can change the stellar X-ray to EUVemission (XUV henceforth) by factors of a few. This also changes the EUVirradiation of orbiting exoplanets. XUV irradiation drives planetary mass-lossand likely shapes the exoplanet population at large. Models predict that XUVirradiation and mass-loss rate are correlated i.e. can be challenged bymeasuring the mass-loss of the same exoplanet during different phases of thehost stars magnetic cycle. The 7 year optical cycle of GJ 436 allows thisexperiment if mirrored in X-rays. Existing X-ray data cover only a very limitedphase space. We propose two new 20 ks observations of GJ 436 to reliably discover the X-ray cycle of GJ 436. [truncated! Please see actual data for full text]