XTE J1650âÂÂ500 is a binary system containing a stellar-mass black hole candidate and 2000âÂÂ2001 transient binary X-ray source located in the constellation Ara. In 2008, it was claimed that this black hole had a mass of 3.8ñ0.5 solar masses, which would have been the smallest found for any black hole; smaller than GRO 1655âÂÂ40, the then known smallest of 6.3 . However, this claim was subsequently retracted; the more likely mass is 5âÂÂ10 solar masses.
The binary period of the black hole and its companion is 0.32 days.