A Planet of Fire and Gas: How Magma Oceans May Explain TOI-270 d’s Mysterious Atmosphere

Matthew C. Nixon and collaborators show that magma-ocean interactions between TOI-270 d’s molten interior and gaseous atmosphere can naturally explain JWST’s detection of H₂O, CH₄, and CO₂ without invoking icy material. Their integrated models link interior chemistry to observable spectra, reproducing the planet’s high metallicity and low C/O ratio. This work suggests that sub-Neptunes’ atmospheres may be strongly shaped by deep, ongoing magma processes.