Astronomers have uncovered evidence of a bizarre, potentially historic discovery: the first moon ever detected beyond our Solar System. Unlike familiar moons, this mysterious object is at least as massive as Jupiter and orbits a brown dwarf, which itself circles a star. The unusual arrangement challenges traditional definitions of planets and moons, leaving scientists unsure what to call it.
Astronomers may have discovered the first moon beyond our Solar System. The star, the point source to the left, has about half the mass of our Sun, and a brown dwarf orbits it, the reddish-brown object seen in the foreground (right). The brown dwarf has about 37 times the mass of Jupiter: too massive to be a planet, but not massive enough to have sustained nuclear fusion like stars.
This brown dwarf is, in turn, orbited by a newly discovered object at least as massive as Jupiter, seen at the center of this image. Kornmesser Astronomers may have found the first moon beyond our Solar System, but the mysterious object is unlike any moon we know. Observations from the European Southern Observatory’s Very Large Telescope (ESO’s VLT) have uncovered evidence of an enormous moon-like body in the CD-35 2722 star system.
