WASP-12b: A Case Study on Ultra-Hot Jupiter Atmospheres
Most gas giant exoplanets have atmospheres dominated by molecular hydrogen (H2). However, on planets where the temperature reaches above ~3000 K a significant fraction of the H2 will thermally dissociate, along with other molecules like H2O; one may call these planets ultra-hot Jupiters (UHJs), rather than just hot Jupiters. Only a handful of known planets have dayside temperatures this high, but the TESS mission is expected to discover hundreds more as it will monitor many early-type stars. With temperatures as hot as M-dwarfs, these UHJs are an interesting intermediate between stars and cooler planets, and they will allow for useful tests of atmospheric models. I will present my recent analysis of Hubble and Spitzer observations and semi-analytical atmospheric modelling of the first-discovered ultra-hot Jupiter, WASP-12b. I will also demonstrate the insights this fiery world can provide, from important opacity sources, to a whole new regime of atmospheric circulation.