XUV irradiation of the Earth-sized planets orbiting TRAPPIST-1

The remarkable discovery of a system of three Earthsized potentiallyhabitableplanets transiting the ultracool dwarf TRAPPIST1 provides an unprecedentedopportunity for detailed study of the atmospheres of terrestrial exoplanets. Ouranalysis of an archival XMMNewton observation of the star revealed XUVradiation that was fifty times stronger than assumed in a theoretical study ofthe planetary atmospheres, with enough XUV irradiation to profoundly modify andperhaps entirely strip those atmospheres. Here we propose a longer XMMNewtonobservation that will cover a full spin cycle of the star and more accuratelydefine the XUV irradiation of the exoplanets. This is an essential step inassessing the habitability of these and similar exoplanets around ultracool dwarfs. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]