Horizontal and vertical exoplanet thermal structure from a JWST spectroscopic eclipse map.

ABSTRACT: Highly irradiated giant exoplanets known 'ultrahot Jupiters' are anticipated to exhibit large variations of atmospheric temperature and chemistry as a function of longitude, latitude and altitude. Previous observations have hinted at these variations, but the existing data have been fundamentally restricted to probing hemisphere-integrated spectra, thereby providing only coarse information on atmospheric gradients. Here we present a spectroscopic eclipse map of an extrasolar planet, resolving the atmosphere in multiple dimensions simultaneously. We analyse a secondary eclipse of the ultrahot Jupiter WASP-18b observed with the Near Infrared Imager and Slitless Spectrograph instrument on the JWST. The mapping reveals weaker longitudinal temperature gradients than were predicted by theoretica

SUBMITTER: Challener RC 

PROVIDER: S-EPMC12708353 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature