Brandon Park Coy is a final year PhD student at the University of Chicago’s Department of the Geophysical Sciences. His research mainly focuses on observations and modelling of small exoplanets’ atmospheres and surfaces with a focus on ‘exo-geology'. He is interested in determining what observations of rocky exoplanets' surfaces can tell us about the geologic history of planets orbiting other stars. He is also interested in the atmospheres of lava worlds, rocky exoplanets so hot that their surfaces are completely molten. He is involved in many collaborations with JWST and PI of a Cycle 3 program investigating the atmospheric origins of a young sub-Neptune.
Title: Towards Population-level Exo-Geology: Characterizing the Surfaces, Atmospheres, and Reflective Properties of Hot Rocky Exoplanets
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. These observations have revealed that most 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.