JWST Climate of TRAPPIST‑1b/c, Finds No Atmosphere
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- University of Bern (with UNIGE and PlanetS) used JWST to map the climate of Earth‑mass rocky exoplanets for the first time.
- TRAPPIST-1b and its sibling TRAPPIST-1c were observed continuously for 60 hours in infrared, covering a full orbit.
- JWST recorded day‑night temperature differences exceeding 500 °C, with day‑side temperatures >200 °C (b) and ≈100 °C (c) and night‑side temperatures <‑200 °C.
- TRAPPIST-1c shows the same extreme contrast, indicating a lack of atmospheric heat redistribution and supporting the conclusion that it has no dense atmosphere.
- Nature Astronomy published the study (Michaël Gillon et al.), confirming that red dwarf radiation can strip atmospheres from close‑in planets.
- TRAPPIST-1e will be the next JWST target to test whether planets in the habitable zone retain atmospheres.
Why it matters: The finding confirms that intense radiation from red dwarf stars can strip atmospheres from close‑in Earth‑size planets, narrowing the pool of potentially habitable worlds and guiding JWST’s future target selection for atmospheric searches. The result also validates climate‑mapping techniques that can be applied to other exoplanets, giving astronomers a new tool to assess planetary environments beyond simple transit spectroscopy.
