Mu Cygni

Proper names: Mu Cygni, 78 Cygni
Catalog numbers:
Gliese (Gl) 836.6, Bonner Durchmusterung (BD) +28°4169, Hipparcos Input Catalog (HIC) 107310, Aitken Double Star (ADS) 15270, Struve (STF) 2822
Heavy element abundance: 60% of Sol
Source for heavy element abundance: Strobel [Fe/H] Determinations
Arity: Both the A and B stars are possible spectroscopic binaries
Right Ascension and Declination: 21h44m8.32s, +28°44'35.3" (epoch 2000.0)
Distance from Sol: 73.1 light-years (22.4 parsecs)
Standard error in distance: 1.5222%
Source for distance: Hipparcos
Celestial (X,Y,Z) coordinates in ly: 53.1, -35.8, 35.1
Galactic (X,Y,Z) coordinates in ly: 10.7, 68.5, -23.2
Proper motion: 0.376 arcsec/yr (129.3° from north)
Radial Velocity: 15.8 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -5.24, 3.29, -42.5

What do all these fields mean?

Data for A and B's orbit around one other:
Combined absolute visual magnitude: +2.74
Combined visual luminosity: 6.95 x Sol
Period: 507.5 years
Semimajor Axis: 95.8 A.U.s
Eccentricity: 0.58
Periastron distance: 40.3 A.U.s
Apastron distance: 151 A.U.s
Year in which periastron occurs: 1962.5
Source for orbit data: W.D. Heintz
As seen from A:
     At periastron, B would appear as magnitude -19.21
     At apastron, B would appear as magnitude -16.33
As seen from B:
     At periastron, A would appear as magnitude -20.52
     At apastron, A would appear as magnitude -17.64

Component A:
Proper names: Mu(1) Cygni
Catalog numbers:
Henry Draper (HD) 206826, Smithsonian Astrophysical Observatory (SAO) 89940, Hoffleit Bright Star (HR) 8309
Spectral class: F4
Luminosity Class: V
Apparent visual magnitude: +4.78
Absolute visual magnitude: +3.03
Visual luminosity: 5.35 x Sol
Diameter: 1.58 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 2.31 A.U.s
Angular size of star in sky in CZ: 0.363923 degrees

Component B:
Proper names: Mu(2) Cygni
Catalog numbers:
Henry Draper (HD) 206827, Smithsonian Astrophysical Observatory (SAO) 89939, Hoffleit Bright Star (HR) 8310
Proper motion: 0.315 arcsec/yr (133.0° from north)
Radial Velocity: 23.5 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -0.78, 12.0, -39.1
Spectral class: G2
Luminosity Class: V
Apparent visual magnitude: +6.09
Absolute visual magnitude: +4.34
Visual luminosity: 1.60 x Sol
Diameter: 1.03 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 1.27 A.U.s
Angular size of star in sky in CZ: 0.433884 degrees

Data for this star system were most recently updated on 4-April-2001.