Astrophysics Seminar – Wed 22nd June 3pm – Vincent van Eylen

This week’s online-only Astrophysics Seminar at 3pm on Wednesday is the last scheduled for the 2021-22 season.

Vincent van Eylen (UCL) will tell us about “The architecture of planets and their host stars”

Abstract: Thousands of exoplanets have now been detected and they exhibit a striking diversity in properties, with system architectures sometimes similar but often starkly different from that of our solar system. In this talk, I show how observable properties of exoplanets can be used to constrain models of planet formation and evolution. In particular, I focus on a gold sample of well-characterized planets for which the host stars are characterized through asteroseismology. I show how such a sample can be used to determine the presence and location of the radius gap, which separates super-Earths and sub-Neptunes. This has provided several key insights: 1) the slope of the radius gap is inconsistent with late gas-poor formation, but matches photo-evaporation models; 2) the complete lack of secure planet detections inside the gap is a result of homogeneous planet core compositions; and 3) these cores have a terrestrial composition, implying in situ formation rather than planet migration from beyond the ice line. Furthermore, I show how we measured differences in orbital eccentricities for systems with one or more transiting planets, and how various models of planet formation and evolution can explain these findings. I conclude with some recent results from the TESS mission and a forward look to PLATO.

The Teams link to connect is

https://teams.microsoft.com/l/meetup-join/19%3ameeting_OWUxNDc4MDItNWRkZS00YWZkLWJlMTktYzZhNjI3YjlhMjA0%40thread.v2/0?context=%7b%22Tid%22%3a%22aebecd6a-31d4-4b01-95ce-8274afe853d9%22%2c%22Oid%22%3a%2218245205-3fea-4456-a63f-afae0cafeaf7%22%7d