Brown dwarf HD 33632 Ab (labeled b) directly imaged by the Subaru Telescope. This brown dwarf orbits a star (behind the circle and plus sign) at a distance of about 20 AU, or 20 Earth-sun distances. That’s similar to the distance from our sun to the planet Uranus. Image via T. Currie/ NAOJ/ NASA-Ames/ Subaru Telescope.
Brown dwarfs are star-planet hybrids, falling somewhere between the masses of giant planets like Saturn and Jupiter, and the smallest stars. All the brown dwarfs we know are outside our own solar system, and they are very dim; their great distances and general dimness makes them hard to photograph directly. In December, though, astronomers using the Subaru Telescope and the Keck Observatory in Hawaii released a new direct image of a brown dwarf that’s one of the best yet obtained. The brown dwarf, called HD 33632 Ab, orbits a sun-like star, HD 33632 Aa, at 86 light-years away.
The new peer-reviewed paper detailing the discovery was published by the researchers in The Astrophysical Journal Letters on November 30, 2020.
By definition, brown dwarfs have between 13 and 80 times the mass of our solar system’s largest planet, Jupiter. That’s the mass range in which ...