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Astrophysics Colloquium

Probing the Escaping Exoplanet Atmospheres
Presented by Antonija Oklopčić
Harvard-Smithsonian Center for Astrophysics

Thursday, January 24, 2019
11:00 A.M. in 169-336

Atmospheric escape is an important process in the evolution of atmospheres of extrasolar planets, especially those orbiting very close to their host stars. However, many aspects of atmospheric escape remain poorly understood, in part due to a small number of direct observations that have been available until recently, obtained mostly via transit spectroscopy in the difficult-to-observe hydrogen Lyman-alpha line. In recent theoretical work (Oklopčić and Hirata, 2018), we demonstrated that the absorption line of helium at 1083 nm can be used as a powerful new diagnostic of escaping atmospheres. Since then, excess absorption in the helium 1083 nm line was observed in several exoplanets, using both space- and ground-based telescopes. These observations opened a new wavelength window into escaping atmospheres that can help us improve our understanding of the physical processes that drive atmospheric mass loss and, consequently, affect planetary evolution and demographics of planetary systems. I will talk about how we can use theoretical models of upper planetary atmospheres to interpret the observed 1083 nm transit absorption signatures and place constraints on the physical properties of extended exoplanet atmospheres and their mass loss rates.

JPL Contact: Trevor David (4-9981)

About the Speaker
Antonija Oklopčić is a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics. She works on theoretical modeling and characterization of exoplanet atmospheres. She obtained her Ph.D. in 2017 from Caltech, where she was advised by Chris Hirata.

SVCP Astrophysics

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