Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cygnus |
Right ascension | 21h 44m 08.57767s [1] |
Declination | 28° 44′ 33.4567″ [1] |
Apparent magnitude (V) | 4.49 [2] |
Characteristics | |
Spectral type | F6V + G2V [3] |
B−V color index | +0.512±0.007 [2] |
Astrometry | |
Radial velocity (Rv) | +16.95 [4] km/s |
Proper motion (μ) |
RA: +257.012
[1]
mas/
yr Dec.: −239.009 [1] mas/ yr |
Parallax (π) | 45.2207 ± 0.2383 mas [1] |
Distance | 72.1 ± 0.4
ly (22.1 ± 0.1 pc) |
Absolute magnitude (MV) | 2.75 [2] |
μ1 Cyg | |
Absolute magnitude (MV) | 2.77 [5] |
Absolute bolometric magnitude (Mbol) | 2.91±0.06 [6] |
μ2 Cyg | |
Absolute magnitude (MV) | 4.38 [5] |
Absolute bolometric magnitude (Mbol) | 4.32±0.06 [6] |
Orbit [7] | |
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 [5] | |
μ1 Cyg | |
Mass | 1.31 M☉ |
Radius | 1.88±0.07 [6] R☉ |
Luminosity | 6.0 L☉ |
Surface gravity (log g) | 3.93 cgs |
Temperature | 6,354 K |
Metallicity [Fe/H] | −0.16 dex |
Rotational velocity (v sin i) | 11.6 km/s |
Age | 3.46 Gyr |
μ2 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 [Fe/H] | −0.24 dex |
Rotational velocity (v sin i) | 6.4 km/s |
Age | 7.11 [5] Gyr |
Other designations | |
μ1 Cyg: HD 206826, HR 8309, SAO 89940 [9] | |
μ2 Cyg: HD 206827, HR 8310, SAO 89939 [10] | |
Database references | |
SIMBAD | μ Cyg |
μ1 Cyg | |
μ2 Cyg |
μ Cygni, Latinised as Mu Cygni, is a binary star [11] 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. [2] The system is located 72 light years distant from the Sun, based on parallax, [1] and is drifting further away with a radial velocity of +17 km/s. [4]
The pair have an orbital period of around 800 years, with a semimajor axis of 5 ″ and an eccentricity around 0.6. [12] The primary, [9] with an apparent magnitude of 4.69, is an F-type main-sequence star with a stellar classification of F6V. [3] It has 35% more mass than the Sun and 188% of the Sun's radius. [6] The star is spinning with a projected rotational velocity of 9.6 km/s. The secondary companion, [10] with an apparent magnitude of 6.12, is a G-type main-sequence star with a class of G2V. [3] It has a similar radius as the Sun and slightly more mass. [6]
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. [3] Component D is the more distant spectroscopic binary HD 206874 (HIP 107326), consisting of two early F-type subgiants. [13]