  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 32m 40.9572s[1] |
| Declination | 41° 14′ 29.279″[1] |
| Apparent magnitude (V) | 11.702 |
| Characteristics | |
| Spectral type | B3–4 Ia+[2] |
| Apparent magnitude (B) | 14.41[3] |
| Apparent magnitude (V) | 11.40[3] |
| Apparent magnitude (J) | 4.667±0.324[4] |
| Apparent magnitude (H) | 3.512±0.260[4] |
| Apparent magnitude (K) | 2.704±0.364[4] |
| U−B color index | 1.69[3] |
| B−V color index | 3.01[3] |
| Variable type | cLBV |
| Astrometry | |
| Radial velocity (Rv) | −11.00[5] km/s |
| Proper motion (μ) | RA: −1.703[1] mas/yr Dec.: −3.412[1] mas/yr |
| Parallax (π) | 0.5895 ± 0.0518 mas[1] |
| Distance | 5,500 ± 500 ly (1,700 ± 100 pc) |
| Absolute magnitude (MV) | −9.82[6] |
| Details | |
| Mass | 110[7] M☉ |
| Radius | 246[7] R☉ |
| Luminosity | 1,660,000[6] L☉ |
| Temperature | 13,700[7] K |
| Age | 3.0[7] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Cygnus OB2 #12 is an extremely luminous blue hypergiant with an absolute bolometric magnitude (all electromagnetic radiation) of −10.9, among the most luminous stars known in the galaxy. This makes the star nearly two million times more luminous than the Sun, although estimates were even higher when the star was first discovered. It is now known to be a binary, with the companion approximately a tenth as bright. A very approximate initial estimate of the orbit gives the total system mass as 120 M☉ and the period as 30 years.
- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ Caballero-Nieves, S. M.; Nelan, E. P.; Gies, D. R.; Wallace, D. J.; Degioia-Eastwood, K.; Herrero, A.; Jao, W.-C.; Mason, B. D.; Massey, P.; Moffat, A. F. J.; Walborn, N. R. (2014). "A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results from the Hubble Space Telescope Fine Guidance Sensors". The Astronomical Journal. 147 (2): 40. arXiv:1311.5087. Bibcode:2014AJ....147...40C. doi:10.1088/0004-6256/147/2/40. S2CID 22036552.
- ^ a b c d Reed, B. Cameron (2003). "Catalog of Galactic OB Stars". The Astronomical Journal. 125 (5): 2531–2533. Bibcode:2003AJ....125.2531R. doi:10.1086/374771.
- ^ a b c Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
- ^ Klochkova, V. G.; Chentsov, E. L. (2004). "The Optical Spectrum of an LBV Candidate in the Cyg OB2 Association". Astronomy Reports. 48 (12): 1005–1018. arXiv:astro-ph/0605483. Bibcode:2004ARep...48.1005K. doi:10.1134/1.1836024. S2CID 55121658.
- ^ a b Oskinova, L. M.; Huenemoerder, D. P.; Hamann, W. -R.; Shenar, T.; Sander, A. A. C.; Ignace, R.; Todt, H.; Hainich, R. (2017). "On the Binary Nature of Massive Blue Hypergiants: High-resolution X-Ray Spectroscopy Suggests That Cyg OB2 12 is a Colliding Wind Binary". The Astrophysical Journal. 845 (1): 39. arXiv:1707.04473. Bibcode:2017ApJ...845...39O. doi:10.3847/1538-4357/aa7e79. S2CID 119537489.
- ^ a b c d Clark, J. S.; Najarro, F.; Negueruela, I.; Ritchie, B. W.; Urbaneja, M. A.; Howarth, I. D. (2012). "On the nature of the galactic early-B hypergiants". Astronomy & Astrophysics. 541: A145. arXiv:1202.3991. Bibcode:2012A&A...541A.145C. doi:10.1051/0004-6361/201117472. S2CID 11978733.