HD 165516
Star in the constellation Sagittarius
From Wikipedia, the free encyclopedia
HD 165516 is a blue supergiant star in the constellation Sagittarius. It is part of the Sagittarius OB1 association and appears against a rich Milky Way starfield near the Trifid Nebula and Lagoon Nebula.
 | |
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 07m 11.35s[1] |
| Declination | −21° 26′ 38.2″[1] |
| Apparent magnitude (V) | +6.33[2] |
| Characteristics | |
| Spectral type | B1/2Ib[3] |
| U−B color index | −0.72[2] |
| B−V color index | +0.12[2] |
| Astrometry | |
| Radial velocity (Rv) | -8.50[4] km/s |
| Proper motion (μ) | RA: −0.23[1] mas/yr Dec.: −1.15[1] mas/yr |
| Parallax (π) | 1.39±0.49 mas[1] |
| Distance | approx. 2,300 ly (approx. 700 pc) |
| Absolute magnitude (MV) | −5.8[5] |
| Details | |
| Mass | 10.1[6] M☉ |
| Radius | 26[7] R☉ |
| Temperature | 25,000[8] K |
| Rotational velocity (v sin i) | 55[9] km/s |
| Age | 22.5[6] Myr |
| Other designations | |
| HR 6762, HD 165516, HIP 88760, BD-21°4855 | |
| Database references | |
| SIMBAD | data |
HD 165516 is close to a small reflection and emission nebula, and an associated loose open cluster. The nebula is catalogued as GN 18.05.6,[10] but was first listed as VdB 113.[11] That name has since been used for the cluster itself, which is likely more distant than HD 165516. The whole cluster is less than a quarter of a degree across, with dozens of members from 8th magnitude downwards. V4381 Sagittarii is listed as a probable member, while HD 165516 and the nearby Wolf-Rayet star WR 111 are considered unlikely to be members.[12]