JWST Detects CS₂ in the Atmosphere of a 20-Myr-old Exoplanet, Revealing Distinct Photochemical Regimes Within a Single System
Using JWST/NIRSpec transmission spectroscopy, researchers detected carbon disulfide (CS₂) at >8σ significance in the atmosphere of V1298 Tau e, a ~20-Myr-old, ~15 M⊕ planet with a Jupiter-like radius. This is the first empirical evidence of CS₂ as a photochemical product in an exoplanet atmosphere, driven by intense UV irradiation of an H/He-dominated envelope. Strikingly, the neighboring planet V1298 Tau b shows SO₂ instead of CS₂, demonstrating that planets within the same system can occupy entirely distinct photochemical regimes — a finding that constrains models of early planetary atmospheric evolution and may indicate divergent formation pathways.