WASP-18 b

WASP-18 b, a gas giant exoplanet 10 times more massive than Jupiter, orbits its star in just 23 hours. Utilizing the Canadian NIRISS instrument on the James Webb Space Telescope, researchers studied the planet during a secondary eclipse, detecting water vapour in its atmosphere. The dayside always faces the star, like the Moon to Earth, and a temperature map revealed a significant temperature shift of up to 540 °C from the hottest point facing the star to the terminator, where the day and night sides meet in perpetual twilight. Temperatures on the planet reach 2,700 °C. (Credits: NASA, JPL-Caltech, K. Miller/IPAC)