Influence of stellar X–ray luminosity distribution and its evolution on exoplanetary mass loss
نویسنده
چکیده
Aims. We investigate the influence of high–energy stellar radiation at close–in orbits on atmospheric mass loss during stellar evolution of a G–type star. Methods. High–energy stellar luminosity varies over a wide range for G field stars. The temporal evolution of the distribution of stellar X–ray luminosity and its influence on the evolution of close–in exoplanets is investigated. X–ray luminosity distributions from the Pleiades, the Hyades and the field are used to derive a scaling law for the evolution of the stellar X–ray luminosity distribution. A modified energy–limited escape approach is used to calculate atmospheric mass loss for a broad range of planetary parameters. Results. We show that the evolution of close–in exoplanets strongly depends on the detailed X–ray luminosity history of their host stars, which varies over several orders– of–magnitude for G stars. Stars located at the high–energy tail of the luminosity distribution can evaporate most of its planets within 0.5 AU, while for a moderate luminosity a significant fraction of planets can survive. We show the change on an initial planetary mass distribution caused by atmospheric escape.
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