The Coldest Planet Ever Seen Is Circling a Stellar Corpse

Astronomers using the James Webb Space Telescope have directly detected the faint glow of a planet that’s colder than any world whose light has been directly observed—an astonishing detection that reveals the extreme conditions of some worlds in our universe. The exoplanet, WD 1856+534 b, was first spotted in 2020 and is twice as old as our solar system. The world is about the size of Jupiter but about six times more massive and much chillier, clocking in at an average temperature of just -125° Fahrenheit (-87° Celsius). That makes it the coldest exoplanet ever directly observed by its own emitted light. The team’s research describing the exoplanet and its thermal emission is currently hosted on the preprint server arXiv. The exoplanet is orbiting a white dwarf, the ghostly ember of a dead star. In fact, that’s what made the object’s detection possible; typically, stars are so bright that they drown out the much duller glow of the planets orbiting them. WD 1856 b’s star is so dim tha ... Read full article.