Sigma(2) Ursae Majoris

light-years
Proper names: Sigma(2) Ursae Majoris, 13 Ursae Majoris, Sigma Ursae Majoris
Catalog numbers:
     Gliese (Gl) 335, Henry Draper (HD) 78154, Bonner Durchmusterung (BD) +67°577, Hipparcos Input Catalog (HIC) 45038, Smithsonian Astrophysical Observatory (SAO) 14788, Aitken Double Star (ADS) 7203, Hoffleit Bright Star (HR) 3616, SFT 1306
Arity: binary
Right Ascension and Declination: 9h10m23.328s, +67°8'2.04" (epoch 2000.0)
Distance from Sol: 66.7 light-years (20.5 parsecs)
Standard error in distance: 1.2528%
Source for distance: Hipparcos
Celestial (X,Y,Z) coordinates in ly: -19.2, 17.5, 61.5
Galactic (X,Y,Z) coordinates in ly: -43.7, 28.5, 41.6
Proper motion: 0.099 arcsec/yr (188.1° from north)
Radial Velocity: -2.9 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -1.97, -9.84, 0.011

What do all these fields mean?

Data for A and B's orbit around one other:
Combined absolute visual magnitude: +3.25
Combined visual luminosity: 4.38 x Sol
Period: 1067.1 years
Semimajor Axis: 127 A.U.s
Eccentricity: 0.814
Periastron distance: 23.6 A.U.s
Apastron distance: 230 A.U.s
Year in which periastron occurs: 1917.7
Source for orbit data: P. Baize
As seen from A:
     At periastron, B would appear as magnitude -17.82
     At apastron, B would appear as magnitude -12.88
As seen from B:
     At periastron, A would appear as magnitude -21.42
     At apastron, A would appear as magnitude -16.48

Data for A and B's orbit, take 2:
Period: 706 years
Semimajor Axis: 100 A.U.s
Eccentricity: 0.75
Periastron distance: 25.1 A.U.s
Apastron distance: 175 A.U.s
Year in which periastron occurs: 1918
Source for orbit data: W. Rabe
As seen from A:
     At periastron, B would appear as magnitude -17.69
     At apastron, B would appear as magnitude -13.47
As seen from B:
     At periastron, A would appear as magnitude -21.29
     At apastron, A would appear as magnitude -17.07


Component A:
Spectral class: F7
Luminosity Class: IV-V
Apparent visual magnitude: +4.84
Absolute visual magnitude: +3.29
Visual luminosity: 4.23 x Sol
Diameter: 1.76 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 2.06 A.U.s
Angular size of star in sky in CZ: 0.456245 degrees


Component B:
Spectral class: K2
Luminosity Class: V
Apparent visual magnitude: +8.44
Absolute visual magnitude: +6.89
Visual luminosity: 0.15 x Sol
Diameter: 0.76 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 0.39 A.U.s
Angular size of star in sky in CZ: 1.034413 degrees

light-years
but not more than light-years away
Data for this star system were most recently updated on 4-April-2001.