The two brown dwarfs form a binary pair called WISE 1049AB that was discovered by NASA‘s Wide-field Infrared Survey Explorer (WISE) in 2013; the duo sits just 6.5 light-years away from us.
They are the closest brown dwarfs to our sun, and thus make an excellent target for the James Webb Space Telescope‘s powerful infrared instruments.
A brown dwarf is an object that isn’t quite massive enough to ignite the nuclear fusion of hydrogen to helium in its core and become a fully fledged star — yet is also considered too massive to be a planet and thought to form like stars do (via the gravitational collapse of a cloud of molecular gas).
As such, brown dwarfs are thought of as a missing link between gas giant planets like Jupiter, and the lowest mass stars, M-dwarfs.
Previous observations have probed the atmosphere of various brown dwarfs, but they have always been limited to time-averaged snapshots, meaning we could not see things in the brown-dwarf atmosphere changing with time.
However, brown dwarfs are fast rotators — WISE 1049A spins on its axis once every 7 hours, and B once every 5 hours — and the conditions in their atmospheres can alter over time, meaning that previous observations that didn’t factor in the objects’ evolutions could have missed lots of variability.
