March 28, 2023
Speaker: Heather Knutson (California Institute of Technology)
Contact Information: hknutso2@caltech.edu
Title: Sub-Neptune, Super-Earth, or Water World? Exploring the Properties of Small Extrasolar Planets
Abstract: We currently know of more than 10,000 planets and planet candidates orbiting nearby stars. This population is dominated by planets with masses between 1-10 times that of the Earth, which can be divided into two broad classes (‘sub-Neptunes’ and ‘super-Earths’) depending on whether or not they host a puffy hydrogen-rich envelope. Most of these planets orbit very close to their host stars, and we expect that their atmospheres should be strongly sculpted by mass loss processes. In the first part of my talk I will present new results from ongoing Keck and Palomar surveys utilizing metastable helium to measure present-day mass loss rates for close-in exoplanets. During the second part of my talk I will focus on M dwarf planetary systems, which represent our best opportunity to study rocky exoplanets with high mean molecular weight atmospheres. Studies have suggested that a subset of M dwarf planets may also possess thick water-rich envelopes, but definitive evidence for the existence of ‘water worlds’ has remained elusive. I will discuss our ongoing efforts to constrain the bulk and atmospheric compositions of M dwarf planets using transit timing variations, and evaluate the prospects for directly measuring their surface and atmospheric properties with the James Webb Space Telescope.
Visitor's room: Room 111A
Visit Schedule:
Tuesday (28 Mar. 2023):
9:30 a.m.: Adam Burrows
10:00 a.m: Gaspar Bakos
10:30 a.m.:
11:00 a.m.: Colloquium
11:30 a.m.: Colloquium
12:00 p.m.: Bahcall lunch
12:30 p.m.: Bahcall lunch
1:00 p.m.: Bahcall lunch
1:30 p.m.: Sam Yee
2:00 p.m.: Tea Time with Grad Students in Grand Central
2:30 p.m.: Tea Time with Grad Students in Grand Central
3:00 p.m.: Jeremy Goodman (129)
3:30 p.m.:
4:00 p.m.: Simon Albrecht
4:30 p.m.: Josh Winn (125)
5:00 p.m.: Yubo Su
Dinner Sign-up - add your name here:
Tuesday (28 Mar. 2023) @ Winberie's
Postdoc Host: Yubo Su
Faculty Host: Josh Winn
Sam Yee
Heather Knutson
Gaspar Bakos
Simon Albrecht
STUDENTS HAVE PRIORITY.
PLEASE NO MORE THAN 8 PEOPLE (it is more difficult to properly interact with the speaker in larger groups).