Jupiter-sized survivor orbits a cooling white dwarf, defying expectations

Astronomers using the James Webb Space Telescope studied WD 1856 b, a Jupiter-sized planet that survived its Sun-like star’s red-giant phase and now orbits a cooling white dwarf about 75 light-years away. The eight-minute grazing transit revealed an atmosphere with methane and hazes, and a surprisingly hot around-400 K temperature, indicating internal reheating rather than just re-radiating energy from the star. The data favor a late inward migration caused by gravitational interactions with distant stellar companions over a common-envelope origin, suggesting more planetary survivors may await discovery near nearby white dwarfs.