"Planet formation at home and abroad: Atmospheric loss and accretion?" by Hilke Schlichting (UCLA)

Date: 
Thursday, October 27, 2016 - 4:00pm to 5:00pm
Series: 
Physics and Astronomy Colloquium

Thursdays, 4:00-5:00 pm

1-434 Physics and Astronomy (map)
Reception from 3:30-4:00 p.m.
(unless otherwise posted)

 

Guest Speaker: Hilke Schlichting (University of California, Los Angeles)

Talk Title:  “Planet formation at home and abroad: Atmospheric loss and accretion”

Abstract:

Recent observations by the Kepler space telescope have led to the discovery of more than 4000 exoplanet candidates consisting of many systems with Earth- to Neptune-sized objects that reside well inside the orbit of Mercury, around their respective host stars. How and where these close-in planets formed is one of the major unanswered questions in planet formation. I will present new results that self-consistently treat the nebular gas accretion onto rocky cores and the subsequent evolution of gas envelopes due to cooling and photo-evaporation following the dispersal of the protoplanetary disk. I will demonstrate that planets shed their outer layers (dozens of percent in mass) following the disk's dispersal (even without photo-evaporation), and that their atmospheres shrink in a few Myr to a thickness comparable to the radius of the underlying rocky core. I will also discuss the roles of collisions in atmospheric loss for both terrestrial planets and exoplanets. I will conclude with discussing the implications of these new results for the origin and formation of Kepler planets and for identifying true Earth analogues.

 

For more information, contact Jay Hauser

We thank the following people for their contributions to the wine fund for the post-colloquium reception:
Prof. Dolores Bozovic, Prof. Mike Cornwall, Prof. Bob Cousins, Prof. Andrea Ghez, Prof. Karoly Holczer, Prof. Eric Hudson, Robert Huff, Prof. Alex Kusenko, Prof. Myank Mehta, Prof. John Miao, Prof. Roberto Peccei, Prof. Claudio Pellegrini, Prof. David Saltzberg, Prof. Jean Turner and Prof. Ben Zuckerman.