LS 5039
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Scutum |
| Right ascension | 18h 26m 15.0568s |
| Declination | −14° 50′ 54.242″ |
| Apparent magnitude (V) | 11.27 |
| Characteristics | |
| Spectral type | O(f)N6.5V + Black hole |
| Astrometry | |
| Radial velocity (Rv) | 17.2 ± 0.7 km/s |
| Proper motion (μ) | RA: 6.826 mas/yr Dec.: −8.515 mas/yr |
| Distance | 8200±300 ly (2500±100 pc) |
| Orbit | |
| Period (P) | 3.90603 ± 0.00017 d |
| Eccentricity (e) | 0.31 ± 0.04 |
| Inclination (i) | 24.9 ± 2.8° |
| Periastron epoch (T) | HJD 2451943.09 ± 0.10 |
| Argument of periastron (ω) (secondary) | 226 ± 8° |
| Semi-amplitude (K1) (primary) | 19.4 ± 0.9 km/s |
| Details | |
| O star | |
| Mass | 22.9+3.4 −2.9 M☉ |
| Radius | 9.3+0.7 −0.6 R☉ |
| Luminosity | 182000 L☉ |
| Surface gravity (log g) | 3.85 cgs |
| Temperature | 39000 K |
| Rotational velocity (v sin i) | 113 km/s |
| Black hole | |
| Mass | 3.7+1.3 −1.0 M☉ |
| Radius | Probably 10.93 km |
| Other designations | |
| V479 Sct, TYC 5702-1197-1, 2MASS J18261505-1450542 | |
| Database references | |
| SIMBAD | data |
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 (likely a black hole) that emits HE (high energy) and VHE (very high energy) 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. Additionally, it is one of the few massive X-ray binaries known to be associated with radio emission.