| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 21 44 08.57767 |
| Declination | 28° 44′ 33.4567″ |
| Apparent magnitude (V) | 4.49 |
| Characteristics | |
| Spectral type | F6V + G2V |
| B−V color index | +0.512±0.007 |
| Astrometry | |
| Radial velocity (Rv) | +16.95 km/s |
| Proper motion (μ) | RA: +257.012 mas/yr Dec.: −239.009 mas/yr |
| Parallax (π) | 45.2207 ± 0.2383 mas |
| Distance | 72.1 ± 0.4 ly (22.1 ± 0.1 pc) |
| Absolute magnitude (MV) | 2.75 |
| μ Cyg | |
| Absolute magnitude (MV) | 2.77 |
| Absolute bolometric magnitude (Mbol) | 2.91±0.06 |
| μ Cyg | |
| Absolute magnitude (MV) | 4.38 |
| Absolute bolometric magnitude (Mbol) | 4.32±0.06 |
| Orbit | |
| Period (P) | 789 yr |
| Semi-major axis (a) | 5.32″ |
| Eccentricity (e) | 0.66 |
| Inclination (i) | 75.5° |
| Longitude of the node (Ω) | 110.1° |
| Periastron epoch (T) | 1958.0 |
| Argument of periastron (ω) (secondary) | 145.7° |
| Details | |
| μ Cyg | |
| Mass | 1.31 M☉ |
| Radius | 1.88±0.07 R☉ |
| Luminosity | 6.0 L☉ |
| Surface gravity (log g) | 3.93 cgs |
| Temperature | 6,354 K |
| Metallicity | −0.16 dex |
| Rotational velocity (v sin i) | 11.6 km/s |
| Age | 3.46 Gyr |
| μ Cyg | |
| Mass | 0.99 M☉ |
| Radius | 1.08±0.05 R☉ |
| Luminosity | 1.4 L☉ |
| Surface gravity (log g) | 4.33 cgs |
| Temperature | 5.998 K |
| Metallicity | −0.24 dex |
| Rotational velocity (v sin i) | 6.4 km/s |
| Age | 7.11 Gyr |
| Other designations | |
| 78 Cyg, BD+28°4169, HIP 107310, CCDM J21442+2845AB, WDS J21441+2845AB | |
| μ Cyg: HD 206826, HR 8309, SAO 89940 | |
| μ Cyg: HD 206827, HR 8310, SAO 89939 | |
| Database references | |
| SIMBAD | μ Cyg |
| μ Cyg | |
| μ Cyg | |
μ Cygni, Latinised as Mu Cygni, is a binary star system in the northern constellation of Cygnus. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.49. The system is located 72 light years distant from the Sun, based on parallax, and is drifting further away with a radial velocity of +17 km/s.
The pair have an orbital period of around 800 years, with a semimajor axis of 5″ and an eccentricity around 0.6. The primary, with an apparent magnitude of 4.69, is an F-type main-sequence star with a stellar classification of F6V. It has 35% more mass than the Sun and 188% of the Sun's radius. The star is spinning with a projected rotational velocity of 9.6 km/s. The secondary companion, with an apparent magnitude of 6.12, is a G-type main-sequence star with a class of G2V. It has a similar radius as the Sun and slightly more mass.
Two reported additional components, C (apparent magnitude 12.93) and D (apparent magnitude 6.94), are believed to be optical doubles rather than part of the Mu Cygni system. Component D is the more distant spectroscopic binary HD 206874 (HIP 107326), consisting of two early F-type subgiants.
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.
- ^ Mason, Brian D.; et al. (December 2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920 Vizier catalog entry
- ^ Maldonado, J.; Martínez-Arnáiz, R. M.; Eiroa, C.; Montes, D.; Montesinos, B. (October 2010), "A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups", Astronomy and Astrophysics, 521: A12, arXiv:1007.1132, Bibcode:2010A&A...521A..12M, doi:10.1051/0004-6361/201014948, S2CID 119209183
- ^ Luck, R. Earle (2017). "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants". The Astronomical Journal. 153 (1): 21. arXiv:1611.02897. Bibcode:2017AJ....153...21L. doi:10.3847/1538-3881/153/1/21. S2CID 119511744.
- ^ Fuhrmann, Klaus (2011). "Nearby stars of the Galactic disc and halo - V". Monthly Notices of the Royal Astronomical Society. 414 (4): 2893–2922. Bibcode:2011MNRAS.414.2893F. doi:10.1111/j.1365-2966.2011.18476.x.
- Pourbaix, D.; et al. (2004), "SB9: The Ninth Catalogue of Spectroscopic Binary Orbits", Astronomy & Astrophysics, 424 (2): 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
- "CCDM J21442+2845AB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-04-08.
- ^ "HR 8309". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 13 January 2014.
- ^ "HR 8310". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 13 January 2014.
- Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976. Vizier catalog entry
- Malkov, O. Yu.; et al. (October 2012), "Dynamical masses of a selected sample of orbital binaries", Astronomy & Astrophysics, 546 (A69): A69, Bibcode:2012A&A...546A..69M, doi:10.1051/0004-6361/201219774 Vizier catalog entry
- Abt, Helmut A (2009). "MK Classifications of Spectroscopic Binaries". The Astrophysical Journal Supplement. 180 (1): 117–118. Bibcode:2009ApJS..180..117A. doi:10.1088/0067-0049/180/1/117. S2CID 122811461.