ASTRONOMY COLLOQUIUM

JWST observations are revealing the chemical compositions and inner workings of exoplanet atmospheres. I will show some initial results, highlighting JWST MANATEE guaranteed time observations of transiting planets ranging from Earth-to-Saturn masses with equilibrium temperatures of 400 - 1000 K. These include the discovery that the Earth-sized planet TRAPPIST-1 b has no substantial atmosphere, a high-confidence detection of CH4 (methane) in a transiting planet, using molecular features and clouds to constrain the core and internal heat of a Neptune-mass planet, the compositions of mini-Neptune planets (unlike any in our Solar System), spatial inhomogeneities on planets' day and night sides, and constraining planet formation pathways. I will also present some lessons learned from analysis and modeling of panchromatic visible-to-mid-infrared exoplanet spectra.