Gliese 569

Gliese 569 is a star in the constellation Boötes. It is orbited by a pair of brown dwarfs. The system lies away.

System

The primary star GJ 569A is orbited by the much fainter secondary GJ 659B at a projected separation of, discovered in 1988. The star GJ 569B itself is a close binary system of two high-mass brown dwarfs in a 2.4-year orbit, and a small magnitude difference between components. The orbital plane of close binary GJ 569Ba and GJ 569Bb is expected to precess at timescales of about 100 thousand years due to the gravitational influence of GJ 569A.

Properties

The primary star Gliese 569A is a flare star. The star was given its variable star designation, CE Boötis, in 1975. The nature of the brown dwarf binary Gliese 569B is highly uncertain, and it was even suspected Gliese 569Ba itself may be either a low-mass star or a binary object. But with a mass about 8-9% that of the Sun means it may possibly be a binary of two extremely low mass ultra-cool dwarf stars that are extremely dim, dim enough to look like a brown dwarf. Both brown dwarfs are weakly variable, likely due to starspot activity.