LS 5039
LS 5039 is a binary system in the constellation of Scutum. It has an apparent magnitude of 11.27, and it is about 8,200 light-years away.
LS 5039 consists of a massive O-type main-sequence star, and a compact object that emits HE and VHE gamma rays. It is one of the only three known star systems of this kind, together with LS I +61 303 and PSR B1259-63. The two objects orbit each other every 3.9 days, along a moderately eccentric orbit.
