Does atmospheric composition actually trace formation? Observing aligned vs misaligned hot Jupiters as a testbed

A primary motivation behind measuring the composition of exoplanetary atmospheres is to understand planet formation and evolution. However, confidently determining a single planet’s formation and evolution history from its atmospheric composition is prevented by the uncertainties and degeneracies inherent to protoplanetary disc composition and planetary evolution. To bypass these uncertainties, and learn how a planet’s formation and evolution influence its current day atmospheric composition, we are undertaking a survey with JWST that is comparing a sample of planets that we know underwent very different evolutionary histories due to their different orbital alignments. Specifically, we are comparing the composition of three hot Jupiters whose orbits are aligned with their host stars’ spin axes with three hot Jupiters that are misaligned. It is believed that aligned hot Jupiters are the outcome of disc migration, while misaligned ones arise from high-eccentricity migration. This dichotomy in their formation and migration pathways leads to differences in the material they accrete during their evolution, which in turn should lead to measurable differences in their atmospheric carbon to oxygen ratio. By comparing the relative composition of an aligned and misaligned hot Jupiter sample, we will test if atmospheric composition depends on planet migration and, thus, if atmospheric composition can be used to make inferences about formation. I will give an overview of our medium category program (GO 3838) and present new theoretical predictions from our state-of-the-art disc chemistry models.