The effect of stellar X-ray radiation on super-Earths through time

The Xray emissions from exoplanet host stars are a key to understanding theevolution of planetary atmospheres. We propose Xray and UV observations of 7stars known to host multiple transiting superEarths. The data will be combinedwith transit spectroscopy and synthesised EUV spectra to provide the crucialinput for detailed atmospheric modelling. The proposed observations will almostdouble the sample of superEarths with well characterised XUV radiationenvironments. The highest priority target is K218 which is the first exoplanetwhere the signature of water has been detected in its atmosphere. This study isdesigned to answer key questions about exoplanet atmospheres, including theirevolution, evaporation, photochemistry and production of biologically significant molecules. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]