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Astrophysics Colloquium

Evaporation of Exoplanet Atmospheres
Presented by David Ehrenreich
Geneva Observatory

Monday, July 16, 2018
12:00 noon in 169-336

Abstract
Many exoplanets are found at extremely short distances from their host stars. As a result, their atmospheres receive a tremendous amount of high-energy irradiation that heats and expands the upper atmospheric layers. These layers eventually escape the planet gravity, forming huge clouds of atomic hydrogen and helium around the planets. I will present new observations of such clouds around a "warm Neptunes" and show new evidence that Neptune-mass exoplanets are a sweet spot for atmospheric escape studies. I will then address the atmospheric heating mechanism that occurs in thermospheres and triggers atmospheric escape. I will demonstrate how it is possible to probe thermospheres of transiting exoplanets using high-resolution spectroscopy and draw perspectives for a combined use of ground-based and space-borne observations in the JWST and ELT era.

JPL Contact: Renyu Hu (4-6090)

About the Speaker
David Ehrenreich obtained his PhD in astrophysics from the Sorbonne University in Paris in 2007. He was a postdoctoral researcher for 5 years at the Institute for Planetary Science and Astrophysics in Grenoble, France, before moving to the University of Geneva in Switzerland in 2012 as a Marie Curie Fellow. Since 2013, he has been the Mission Scientist of the CHEOPS mission of the European Space Agency. He was appointed Associate Professor at the University of Geneva in 2017. His main research interest is the atmospheric characterization of exoplanets.


SVCP Astrophysics


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