75 Cygni
75 Cygni is a binary star[6] 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.[2] 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.[1]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 21h 40m 11.10795s[1] |
| Declination | +43° 16′ 25.8161″[1] |
| Apparent magnitude (V) | 5.09[2] |
| Characteristics | |
| Evolutionary stage | red giant |
| Spectral type | M1IIIab[3] |
| B−V color index | 1.601±0.006[2] |
| Variable type | suspected[4] |
| Astrometry | |
| Radial velocity (Rv) | −29.25±0.14[1] km/s |
| Proper motion (μ) | RA: +62.366[1] mas/yr Dec.: +15.488[1] mas/yr |
| Parallax (π) | 7.5210 ± 0.1706[1] mas |
| Distance | 434 ± 10 ly (133 ± 3 pc) |
| Absolute magnitude (MV) | −0.36[2] |
| Details | |
| Radius | 44.61+3.12 −7.77[1] R☉ |
| Luminosity | 438.5±11.5[1] L☉ |
| Temperature | 3,954+397 −131[1] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
The pair had an angular separation of 2.7″ as of 2008, with the companion having a visual magnitude of 10.7.[6] The brighter magnitude 5.18[6] primary is an aging red giant star with a stellar classification of M1IIIab.[3] Having exhausted the supply of hydrogen at its core, it has expanded to around 45[1] times the radius of the Sun. It is a suspected variable star of unknown type and amplitude.[4] The star is radiating 439[1] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,954 K.[1]
An optical companion, with a spectral type of K, is a few arcseconds away and has an apparent magnitude of 10.14.[7]
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.
- 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.