Astronomy Colloquium Speaker Calendar

Exoplanet atmospheres are exciting laboratories to probe unique chemical and physical processes in a regime not accessible elsewhere in the universe.  Through observations and modelling, I probe the conditions and evolutionary processes on a wide variety of worlds.  Small rocky planets orbiting M dwarfs are our only chance of finding exoplanetary biosignatures in the near future, but whether they can even hold on to atmospheres is unknown.  To find out, I use JWST thermal emission observations of their day and night sides to look for atmospheric circulation.  Their bigger mini-Neptunes cousins, with radii and densities between that of Earth and Neptune, are unlike any planet in the solar system.  My multi-wavelength all-sky survey of atmospheric escape from young and intermediate-age mini-Neptunes shows that they have primordial atmospheres which are quickly being photoevaporated, potentially transforming them into a smaller, denser class of planet within a few Gyr.  These observations constrain the efficiency of mass loss, the atmospheric metallicity, and the planetary magnetic field, the last of which is difficult to constrain in any other way.  In the final part of my talk, I will highlight the importance of open-source software–including my atmospheric retrieval code PLATON–to studying planets of all types, from super-Earths to mini-Neptunes to hot Jupiters.  I will also synergize the different aspects of my research to offer a vision for the future of biosignature searches.