October 19
Towards Population-level Exo-Geology: Characterizing the Surfaces, Atmospheres, and Reflective Properties of Hot Rocky Exoplanets
Speaker: Brandon Park Coy, University of Chicago
Abstract: Studying the prevalence and origins of atmospheres on rocky exoplanets is a key goal of astrophysics and astrobiology. The James Webb Space Telescope (JWST) is providing the first population-level constraints on the thermal emission of rocky exoplanets orbiting small M stars (‘M-Earths’). These observations have revealed that the majority of these planets lack thick, Venus-like atmospheres and are likely ‘bare rocks’. In this case, however, thermal emission probes surface properties of the planet. I will show that analyzing these observations homogenously on a population-level can provide the first constraints on ‘exo-geology’ occurring in exoplanet systems.
Contrary to M-Earths, there is growing evidence for substantial atmospheres on lava worlds, small, primarily rocky planets hot enough to melt their silicate surfaces. I will present results from the LAVALAMPS survey, a JWST program measuring the thermal emission 10 lava worlds to better constrain the origins of these atmospheres. I will also present results from a systematic study of the TESS phase curves of small planets, reporting new detections of the visible light phase curves of 5 lava worlds. Combined with previous observations from Kepler, these results show that lava worlds generally are moderately-to-highly reflective in contrast to the very dark hot Jupiters at similar temperatures.
Host: Yoni Brande