Solar System Scale super-Jupiters are Metal Rich: Insights from a High Contrast JWST CO2 Census

The formation pathways of super-Jovian exoplanets are uncertain: did they form top down like stars
and brown dwarfs, or bottom up like other exoplanets? Planets formed by core accretion should
exhibit distinct, enriched abundances compared to their host, but correlated noise, telluric contamina-
tion, and limited wavelength coverage has precluded the unambiguous measurements of these planets’
metallicities. High contrast observations from JWST are revealing key compositional clues in the spec-
tra of directly imaged planets that are inaccessible from the ground, like CO2, and finally revealing
temperate giant planets. I will present on novel coronagraphic images of a sample of systems using
the NIRCam coronagraphs. These images have achieved the first CO2 detection on a directly imaged
planet (Balmer et al. 2025b) and opened the door to studying the distribution of metallicities for wide
separation giants as a function of their dynamical masses. These results necessitate a reimagining of
giant planet enrichment during the gas accretion stage.