When we observe exoplanets, we generally expect to see clouds in their atmospheres, just like our own planet and many others in our solar system. Hot Jupiters in particular are expected to have a variety of species like iron, corundum, and silicates condensing in their atmospheres. However, atmospheres experience radiative feedback from these clouds -- that is, the clouds change the temperature and wind structure of the atmosphere, and the climate in the atmosphere can in turn affect the behavior of clouds. These cloudy effects can also impact our observations of atmospheres. In light of recent unexplained JWST observations of hot Jupiters, we need to improve the parameterizations of clouds in our dynamics models to reflect that radiative feedback as accurately as possible and improve our interpretations of observations.

tldr; clouds can modify hot Jupiter atmospheres and impact our observations of them, so we need better cloud & dynamics models to understand what's going on.

Research objectives

We are working to improve our understanding of hot Jupiter atmospheres by indirectly coupling a 3D general circulation model (GCM) with a 1D cloud microphysics model. By feeding information back and forth between the dynamics model and the cloud formation model, we're hoping to obtain physically-informed results while keeping computational costs relatively low.

Results

Right now, we are post-processing our atmospheric models to generate emission spectra and phase curves that we can compare to existing JWST results. Stay tuned for the paper!

Planets that experience strong irradiation -- from proximity to their star or from stellar flares for example -- can undergo atmospheric escape, where light elements like hydrogen escape from a planet's atmosphere into space. With JWST's ongoing search for rocky planet atmospheres, it's more important than ever to understand how atmospheric escape shapes a planet's atmospheric evolution and which planets can be affected by it.

Research objectives

Using the VPLanet software, we ran atmospheric escape simulations for a system of small rocky planets around an M-dwarf, the L 98-59 system, to learn about the planets' likelihood of water retention given various water-rich compositions. This system is well-studied and now a prime target for JWST for its ease of observability and likelihood of atmospheric detection. 

Results

We find that all three planets modeled should accumulate important amounts of oxygen due to water photolysis, while experiencing significant water loss. In all simulated scenarios, JWST should be sensitive to detections of retained oxygen, especially for planets b and c which are the most promising targets.