A0620-00

A0620-00 (abbreviated from 1A 0620-00) is a binary star system in the constellation of Monoceros, with an apparent magnitude of 11.2.

A0620-00 consists of two objects. The first object is a K-type main-sequence star. The second object cannot be seen, but based on its calculated mass of about solar mass|, it is too massive to be a neutron star and must therefore be a stellar-mass black hole. The two objects orbit each other every 7.75 hours. At a distance of roughly away, the black hole of A0620-00 would be one of the nearest known black holes to the Solar System, closer than GRO J1655-40.