JWST Maps Uneven Atmosphere of WASP-17b

JWST observations have revealed uneven contours in the atmosphere of hot Jupiter WASP-17b, using a technique called “transmission strings” to map different parts of the planet’s edge rather than averaging them together. ^[2][3]

The method tracks the planet as it passes in front of its star, measuring starlight filtered through its atmosphere from different angles. Researchers found the evening side near the equator is more extended than the cooler morning side, a pattern consistent with winds carrying heat from the planet’s permanently lit side toward its night side. ^[2][3]

The study also reports temperature and chemical-composition patterns consistent with theoretical predictions and other modeling. This is a demonstration on WASP-17b, not evidence that the method has mapped other planets or established weather patterns across exoplanets; researchers describe broader mapping as a future possibility. ^[2][3]