From dusk till dawn

Ultrahot exoplanet, atmospheric differences: Researchers discovered clear differences in the atmosphere between the morning and evening sides of the ultrahot gas planet WASP-121 b using the James Webb Space Telescope (JWST). Temperature and chemical variations: The evening side absorbs more infrared light due to higher temperatures caused by strong winds moving heat eastward, while water molecules decrease in the evening terminator due to high temperatures breaking them apart. Planetary rotation and observation method: WASP-121 b’s synchronous rotation reveals different atmospheric regions during transit, allowing scientists to analyse changes in light absorption over time and longitude.

Raccontata daeurekalert.org