The high-energy environment and atmospheric escape of small exoplanets

Leonardo dos Santos (University of Geneva)
Friday, October 2, 2020 - 10:00am to 11:00am

Similarly to stars, planets also lose mass with time, even our own Earth. In particular, hot extrasolar planets orbiting close to their host stars are subject to large mass loss rates due to heating by high-energy irradiation and subsequent atmospheric escape. This process is so pervasive among hot planets that it imprints features in the population of transiting exoplanets, such as the hot-Neptune desert and the photoevaporation valley of super-Earths. Are small planets able to fight atmospheric escape and retain their primary atmospheres? If so, for how long? In this seminar, I will briefly go over some recent advances in observing the upper atmospheres of small transiting exoplanets aiming to constrain their rates of atmospheric escape and their high-energy environment. I will also present the main challenges of these observations, in particular the impact of stellar activity, and the preliminary results of a recent observation campaign to detect the upper atmosphere of a young transiting planet. Finally, I will discuss what are the best targets to observe atmospheric escape, and the future prospects for research.

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