JWST Maps Gem-Like Features in the Atmosphere of a Puffy Hot Jupiter
Astronomers used James Webb Space Telescope observations to study WASP-17b, a low-density exoplanet about 1,300 light-years away that is roughly twice Jupiter's width. A technique called transmission strings revealed a ring-shaped atmospheric structure with prominent gem-like features rising from it. The planet is tidally locked, with a scorching dayside facing its star and a cooler nightside facing space.
WASP-17b orbits roughly 1,300 light-years away and completes one circuit in less than four Earth days. Although its mass is about four-fifths Jupiter’s, its diameter is about double, making it an unusually low-density, puffy hot Jupiter.
Using JWST, researchers applied transmission strings to sample the planet’s atmospheric edge from multiple angles during transits. This produced a ring-like profile with localized “gem” features, including a bulge where hot equatorial winds meet the cooler nightside.
This finding may deepen public interest in exoplanet science and show how JWST data can reveal atmospheric structure beyond simple averages. It could inform future atmospheric models and observing strategies, benefiting astronomers, educators, and science communicators. For general audiences, vivid descriptions of distant “gem” features may make planetary science more accessible, though direct societal effects remain indirect and speculative.