A giant planet's atmosphere is so chemically different from its own star that it 'proves' the planet grew by cannibalizing space debris.
April 14, 2026
Original Paper
Direct Images of CO2 Absorption in the Atmosphere of a Super-Jupiter: Enhanced Metallicity Suggestive of Formation in a Disk
arXiv · 2604.09785
The Takeaway
Directly imaging CO2 on a 'Super-Jupiter' revealed it has way more heavy elements than the star it orbits. This is a 'smoking gun' for planet formation models, showing that large planets are built from disks of solid debris rather than just collapsing from gas clouds.
From the abstract
It is unclear how directly imaged substellar companions with masses near the deuterium burning limit form, because these objects are rare and their bulk properties are not diagnostic of their formation. In this paper we revisit this problem using JWST/NIRCam coronagraphic images of the 29 Cygni (=HIP 99770) system that reveal the recently-discovered super-Jovian companion 29 Cyg b at wavelengths covering 4-5${\mu}$m for the first time. This object has an uncertain mass that straddles the deuteri