Overview
- A Nature Astronomy paper published October 28 reports the first three-dimensional temperature map of exoplanet WASP-18b.
- The dayside map reveals a central substellar hotspot encircled by a cooler ring near the limbs, with the hottest region showing lower water vapor consistent with water breaking apart.
- Researchers reanalyzed a JWST NIRISS secondary-eclipse observation across many wavelengths, enabling temperature measurements by latitude, longitude, and altitude.
- Measured east–west temperature differences are smaller than predicted by some models, suggesting effects from hydrogen dissociation and possibly nightside clouds.
- The authors say the 3D eclipse-mapping technique can be extended to other JWST-observed planets, and further observations are planned to improve spatial resolution.