LS 5039
A broad-band optical light curve for V479 Scuti, adapted from Sarty et al. (2011) | |
| 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.
The "LS" in the system's name refers to the Luminous Stars catalogue which was published by Charles Bruce Stephenson and Nicholas Sanduleak in 1971. In 2001, J. Simon Clark et al. announced that LS 5039 varies in brightness. For that reason, it was given the variable star designation V479 Scuti, in 2006. It is considered to be a possible microquasar.
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.