James Webb Space Telescope detects shifting water clouds on brown dwarf

Astronomers using the James Webb Space Telescope (JWST) have discovered the first evidence of changing water clouds on a celestial body outside our solar system. The study focused on WISE 0855, the coldest known brown dwarf, located approximately 7.5 light-years away.

Led by Brittany Miles of the University of Arizona’s Steward Observatory, the team observed the object for 11 hours, recording its light spectrum every 15 minutes. The data reveals that the atmosphere of WISE 0855 is shaped by two simultaneous processes: high-altitude water clouds that thicken and thin as the object rotates, and chemical gases rising from deep within via convection.

Previously, telescopes could not distinguish between the effects of clouds, chemical composition, and temperature. The JWST data allows scientists to separate these signals for the first time, providing a detailed view of the weather patterns on this massive, sub-stellar object.