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A Lava World Dimmed Like It Still Had Air
One JWST partial eclipse placed TOI-431b below the brightness expected from a bare, dark rock, though only at 1.8 sigma.
Summary
One JWST partial eclipse placed TOI-431b below the brightness expected from a bare, dark rock, though only at 1.8 sigma.
MIRI measured an 81 ± 16 parts-per-million eclipse from TOI-431b, corresponding to a dayside brightness temperature near 1,967 kelvin. The brightness ratio sits 1.8 sigma below a zero-albedo, zero-redistribution bare-rock model. Because exposed magma is expected to be dark, the team says an atmosphere best explains the lower observed emission through reflection or heat transport. The evidence comes from one partial eclipse and remains tentative; composition and stronger constraints require future observations and improved lava-planet models.
Why it matters
One JWST partial eclipse placed TOI-431b below the brightness expected from a bare, dark rock, though only at 1.8 sigma.
Limits and context
No additional limitation was separately recorded.
Key claims
One JWST partial eclipse placed TOI-431b below the brightness expected from a bare, dark rock, though only at 1.8 sigma.
Evidence: source-2026-09-05-005
Sources
- arXiv preprint 2609.03029arXiv · primary research
Corrections
No corrections have been recorded for this story.