JWST maps the lopsided atmosphere of exoplanet WASP-17 b

Astronomers from Bristol and Cornell used the James Webb Space Telescope to map an exoplanet's atmosphere along its limb for the first time. The hot Jupiter WASP-17 b has an atmosphere 1.8 times thicker at its evening terminator than at its morning edge, with temperatures of 1522 K versus 858 K.

• WASP-17 b lies about 1,300 light years away in Scorpius
• Temperature gap between evening and morning limbs is 650 K
• The hotter side's atmosphere is 1.8 times more extended
• Water and CO₂ are evenly spread; methane and SO₂ persist near the poles