DIX Planetary Science Seminar

Hot Jupiters are compelling targets for thermal emission observations because their high signal-to-noise allows precise atmospheric characterization. Theory originally predicted that cooler planets would show absorption features in their secondary eclipse spectra due to having uninverted atmospheres, while warmer planets would have inverted atmospheres causing emission features in their eclipse spectra. I will first discuss early observations of ultra-hot Jupiters, which led to the realization that these hottest exoplanets are a distinct class with unique high-temperature chemistry. I will then present new models which take into account this new high-temperature chemistry, and show how they can explain the featureless spectra we observe in many ultra-hot Jupiters. However, observed hot Jupiters still show a surprising level of diversity in their eclipse spectra. To further examine this diversity, we performed a population study of all secondary eclipse observations of hot Jupiters with the Hubble Space Telescope (HST). From this population study we propose that the spectra of hot Jupiters can be explained through compositional diversity in their atmospheres.

In the coming years we will have the opportunity to study hot Jupiter atmospheres in even more detail using the James Webb Space Telescope (JWST). In particular, JWST will provide the unique capability to perform spectroscopic eclipse mapping, which will allow us to map the atmospheres of hot Jupiters in three dimensions (latitude, longitude, and altitude). I will present a new method to analyze eclipse mapping observations which can be used to interpret these complicated data sets without relying on expectations from circulation models. Finally, I will discuss ongoing observations of hot Jupiters which I will be leading in the coming years using both HST and ground-based high-resolution observations.