BOWIE-ALIGN: Comparing Orbital Alignments and Atmospheric Compositions - James Kirk and Evie Ahrer

"BOWIE-ALIGN: Comparing Orbital Alignments and Atmospheric Compositions to Probe Hot Jupiter Origins" Abstract: More than 30 years after their discovery, the formation of hot Jupiters remains uncertain. Their atmospheres have long been thought to hold information vital to understanding their origins. In particular, the carbon-to-oxygen ratio (C/O) is theorised to depend on where a hot Jupiter accreted its atmosphere relative to the volatile ice lines of the protoplanetary disc within which it formed. However, the formation–compositon connection can be obscured by myriad chemical and dynamical processes, raising questions about the general utility of using atmospheres to learn about formation. Motivated by these uncertainties, we conducted an observing campaign with JWST (“BOWIE-ALIGN”) to test whether planets with different orbital alignments, expected to trace different migration histories, exhibit corresponding differences in atmospheric composition. Aligned hot Jupiters are typically associated with disc migration, whereas misaligned hot Jupiters are often attributed to migration after the dispersal of the disc. Therefore, if alignment traces a planet’s migration through a disc, it should also result in a difference in the material accreted by the planet during its evolution. We will present the full BOWIE-ALIGN sample of four misaligned and three aligned hot Jupiters to test whether atmospheric composition differs for these dynamically distinct populations and thus the utility of atmospheres as a probe of formation.