BM Scorpii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 17h 40m 58.54640s |
| Declination | −32° 12′ 52.0644″ |
| Apparent magnitude (V) | 5.25 – 6.46 |
| Characteristics | |
| Spectral type | K2Ib Hδ1 |
| Variable type | SRd |
| Astrometry | |
| Radial velocity (Rv) | −7.39 km/s |
| Proper motion (μ) | RA: −0.895 mas/yr Dec.: −6.073 mas/yr |
| Parallax (π) | 2.0344±0.0681 mas |
| Distance | 1,600 ± 50 ly (490 ± 20 pc) |
| Absolute magnitude (MV) | −2.57 |
| Details | |
| Mass | 5-9 M☉ |
| Radius | 129 R☉ |
| Luminosity | 3,388 L☉ |
| Surface gravity (log g) | 1.1 cgs |
| Temperature | 3,888 K |
| Metallicity [Fe/H] | −0.22 dex |
| Other designations | |
| BM Sco, CD−32°13142, HD 160371, HIP 86527 | |
| Database references | |
| SIMBAD | data |
BM Scorpii (BM Sco) is a red supergiant and a semiregular variable star located in the constellation Scorpius. It lies approximately 490 parsecs (1,600 ly) away in the open cluster Messier 6, the Butterfly Cluster. Although its brightness varies, it is at least occasionally visible to the naked eye of an observer with dark skies far from city lights.