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Recorded video: YouTube, Bilibili

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Abstract:

Nearly a decade has passed since the discovery that planets with sizes intermediate between that of the Earth and Neptune (“super-Earths” or “mini-Neptunes”, depending on their densities) dominate the observed population of close-in exoplanets. These planets have no solar system analogue, yet a significant fraction of Sun-like stars appear to have at least one (and often more) interior to Mercury’s orbit.  In my talk I will describe ongoing efforts to characterize the bulk and atmospheric compositions of these planets, and to explore their past formation and migration histories.

About the speaker:

Heather Knutson is a professor of planetary science in the Division of Geological and Planetary Sciences at the California Institute of Technology.  She obtained her BS in physics from Johns Hopkins University in 2004, and her PhD in astronomy from Harvard University in 2009.  She then spent two years as a Miller Postdoctoral Fellow at the University of California, Berkeley before beginning her faculty position at Caltech.  She is the recipient of the Annie Jump Cannon Award and the Newton Lacy Pierce Prize from the American Astronomical Society, as well as the Paolo Farinella Prize from the Europlanet Society.  Her research focuses on using the present-day properties of exoplanetary systems to explore how planetary systems form and evolve.

Audience in the world:

(image credit: timeanddate.com)

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Recorded video: YouTube, Bilibili

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Abstract:

I will present the results of new 3-D Global Climate Model (GCM) simulations aimed at reproducing the conditions of primordial surface water condensation and thus of the formation of oceans on terrestrial planets. The simulations reveal that clouds preferentially form on the nightside of young and hot telluric planets endowed with a water-rich atmosphere. These clouds have thus a net warming effect that effectively prevents the formation of surface liquid water oceans. I will show how this result has important implications for the past and present habitability of Earth, Venus and exoplanets.

About the speaker:

Dr. Martin Turbet is currently a CNRS research scientist working at the “Laboratoire de Météorologie Dynamique” a.k.a. LMD, in Paris. After defending the PhD thesis at LMD in 2018, and a short-term postdoctoral visit at the Department of Geophysical Sciences of the University of Chicago, he did three years of postdoc at the Astronomical Observatory of the University of Geneva. His research work lies at the interface between astrophysics, climate sciences and geophysics. The main expertise of Dr. Turbet is the development and use of sophisticated numerical atmospheric models to study the climates of terrestrial planets located inside the Solar System (Mars, Earth and Venus) and outside (exoplanets). He also works on spectroscopic measurements in the lab (to measure gas opacities) and with telescopes (to study the properties of the atmospheres of telluric planets).

Audience in the world:

(image credit: timeanddate.com)

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