| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 21 40 11.10795 |
| Declination | +43° 16′ 25.8161″ |
| Apparent magnitude (V) | 5.09 |
| Characteristics | |
| Evolutionary stage | red giant |
| Spectral type | M1IIIab |
| B−V color index | 1.601±0.006 |
| Variable type | suspected |
| Astrometry | |
| Radial velocity (Rv) | −29.25±0.14 km/s |
| Proper motion (μ) | RA: +62.366 mas/yr Dec.: +15.488 mas/yr |
| Parallax (π) | 7.5210 ± 0.1706 mas |
| Distance | 434 ± 10 ly (133 ± 3 pc) |
| Absolute magnitude (MV) | −0.36 |
| Details | |
| Radius | 44.61+3.12 −7.77 R☉ |
| Luminosity | 438.5±11.5 L☉ |
| Temperature | 3,954+397 −131 K |
| Other designations | |
| 75 Cyg, NSV 13834, BD+42°4177, GC 30338, HD 206330, HIP 106999, HR 8284, SAO 51167, WDS J21402+4316 | |
| Database references | |
| SIMBAD | data |
75 Cygni is a binary star system in the northern constellation of Cygnus. It is visible to the naked eye as a dim, reddish-hued point of light with an apparent visual magnitude of 5.09. The system is located at a distance of about 434 light years from the Sun, based on parallax, and is drifting closer with a radial velocity of −29 km/s.
The pair had an angular separation of 2.7″ as of 2008, with the companion having a visual magnitude of 10.7. The brighter magnitude 5.18 primary is an aging red giant star with a stellar classification of M1IIIab. Having exhausted the supply of hydrogen at its core, it has expanded to around 45 times the radius of the Sun. It is a suspected variable star of unknown type and amplitude. The star is radiating 439 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,954 K.
An optical companion, with a spectral type of K, is about an arcminute away and has an apparent magnitude of 10.14.
References
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373, S2CID 123149047.
- ^ Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, GCVS 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
- "75 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-07-22.
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- "BD+42 4177C". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-07-22.