Abstract:  From the success of multiple exoplanet survey missions, we now know that low-mass planets are the most common type of exoplanets in our galaxy. However, for a given mass, the sizes of these low-mass planets can vastly differ from Earth-sized to nearly the size of Jupiter. Lopez and Fortney (2014) showed that this size difference is directly correlated to the amount of H/He planets possess. Why then do some of these low-mass planets manage to accrete and maintain significant H/He envelopes that can make up more than 20% of their masses while others of a similar mass lose theirs (or formed with no atmosphere)? Since atmospheres encode the formation and evolutionary histories of planets, determining their composition and structure is essential for answering this question. Using Hubble/WFC3-IR, we observed the transmission spectra of the rocky super-Earth GJ 1132b and the super-puffs Kepler-51b and -51d in an attempt to determine their atmospheric compositions. I will present our results from these two studies and discuss what their spectra could mean both for their respective populations and for low-mass planets as a whole.

Please click the link to join the webinar: https://psu.zoom.us/s/98744005110