Castor

light-years
Proper names: Castor, Alpha Geminorum, 66 Geminorum, The Horseman
Catalog numbers:
     Gliese (Gl) 278, Bonner Durchmusterung (BD) +321581, Hipparcos Input Catalog (HIC) 36850, Aitken Double Star (ADS) 6175, Struve (STF) 1110
Heavy element abundance: 390% of Sol
Standard error in heavy element abundance: 37%
Source for heavy element abundance: Strobel [Fe/H] Determinations
Arity: hexary (!!)
Right Ascension and Declination: 7h34m36s, +31°53'18" (epoch 2000.0)
Distance from Sol: 51.6 light-years (15.8 parsecs)
Standard error in distance: 1.907%
Source for distance: Hipparcos
Celestial (X,Y,Z) coordinates in ly: -17.6, 40.1, 27.2
Galactic (X,Y,Z) coordinates in ly: -47.0, -6.44, 20.2
Proper motion: 0.198 arcsec/yr (238.9° from north)
Radial Velocity: 6 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -10.7, -4.63, -11.0

What do all these fields mean?

Data for (A1-A2) and (B1-B2)'s orbit around one other:
Combined absolute visual magnitude: +0.55
Combined visual luminosity: 52.3 x Sol
Period: 511.3 years
Semimajor Axis: 116 A.U.s
Eccentricity: 0.36
Periastron distance: 74.5 A.U.s
Apastron distance: 158 A.U.s
Year in which periastron occurs: 1950.65
Source for orbit data: P. Muller
As seen from (A1-A2):
     At periastron, (B1-B2) would appear as magnitude -20.36
     At apastron, (B1-B2) would appear as magnitude -18.72
As seen from (B1-B2):
     At periastron, (A1-A2) would appear as magnitude -21.27
     At apastron, (A1-A2) would appear as magnitude -19.63

Data for (A1-A2) and (B1-B2)'s orbit, take 2:
Period: 420.07 years
Semimajor Axis: 99.5 A.U.s
Eccentricity: 0.33
Periastron distance: 66.7 A.U.s
Apastron distance: 132 A.U.s
Year in which periastron occurs: 1965.3
Source for orbit data: W. Rabe
As seen from (A1-A2):
     At periastron, (B1-B2) would appear as magnitude -20.60
     At apastron, (B1-B2) would appear as magnitude -19.11
As seen from (B1-B2):
     At periastron, (A1-A2) would appear as magnitude -21.51
     At apastron, (A1-A2) would appear as magnitude -20.02

Data for (A1-A2) and (B1-B2)'s orbit, take 3:
Period: 380 years
Semimajor Axis: 93.9 A.U.s
Eccentricity: 0.37
Periastron distance: 59.2 A.U.s
Apastron distance: 129 A.U.s
Year in which periastron occurs: 1968.8
Source for orbit data: Strand
As seen from (A1-A2):
     At periastron, (B1-B2) would appear as magnitude -20.86
     At apastron, (B1-B2) would appear as magnitude -19.17
As seen from (B1-B2):
     At periastron, (A1-A2) would appear as magnitude -21.77
     At apastron, (A1-A2) would appear as magnitude -20.08

Data for A1 and A2's orbit around one other:
Combined absolute visual magnitude: +0.94
Combined visual luminosity: 36.5 x Sol
Period: 9.2127 days
Semimajor Axis: 0.022 A.U.s
Eccentricity: 0.499
Periastron distance: 0.011022 A.U.s
Apastron distance: 0.032978 A.U.s
Source for orbit data: Burnham's Celestial Handbook
Comfort Zone (visual) around both: 6.04 A.U.s
As seen from A1:
     At periastron, A2 would appear as magnitude -39.66
     At apastron, A2 would appear as magnitude -37.29
As seen from A2:
     At periastron, A1 would appear as magnitude -39.66
     At apastron, A1 would appear as magnitude -37.29

Data for B1 and B2's orbit around one other:
Combined absolute visual magnitude: +1.85
Combined visual luminosity: 15.8 x Sol
Period: 2.92828 days
Semimajor Axis: 0.03 A.U.s
Eccentricity: 0
Periastron distance: 0.03 A.U.s
Apastron distance: 0.03 A.U.s
Source for orbit data: Burnham's Celestial Handbook
Comfort Zone (visual) around both: 3.98 A.U.s
As seen from B1:
     At periastron, B2 would appear as magnitude -36.58
     At apastron, B2 would appear as magnitude -36.58
As seen from B2:
     At periastron, B1 would appear as magnitude -36.58
     At apastron, B1 would appear as magnitude -36.58

Data for C1 and C2's orbit around one other:
Combined absolute visual magnitude: +8.07
Combined visual luminosity: 0.051 x Sol
Period: 19.539414 hours
Semimajor Axis: 0.018 A.U.s
Source for orbit data: Burnham's Celestial Handbook
Comfort Zone (visual) around both: 0.23 A.U.s
As seen from C1:
     C2 would appear as magnitude -31.47
As seen from C2:
     C1 would appear as magnitude -31.47

Data for ((A1-A2)-(B1-B2)) and (C1-C2)'s orbit around one other:
Combined absolute visual magnitude: +0.55
Combined visual luminosity: 52.4 x Sol
Period: 10000 years
Observed Separation: 1146 A.U.s
Year of separation observation: 1955
As seen from ((A1-A2)-(B1-B2)):
     (C1-C2) would appear as magnitude -8.20
As seen from (C1-C2):
     ((A1-A2)-(B1-B2)) would appear as magnitude -15.72


Component A1:
Catalog numbers:
     Henry Draper (HD) 60179, Hoffleit Bright Star (HR) 2891
Spectral class: A1
Luminosity Class: V
Apparent visual magnitude: +2.69
Absolute visual magnitude: +1.70
Visual luminosity: 18.3 x Sol
Mass: 2 x Sol
Diameter: 2.28 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 4.27 A.U.s
Orbital period in CZ: 6.2479 years
Tidal index in CZ: 0.025617
Angular size of star in sky in CZ: 0.283921 degrees


Component A2:
Catalog numbers:
     Hoffleit Bright Star (HR) 2891
Spectral class: A2
Luminosity Class: V
Apparent visual magnitude: +2.69
Absolute visual magnitude: +1.70
Visual luminosity: 18.3 x Sol
Mass: 2 x Sol
Diameter: 2.28 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 4.27 A.U.s
Orbital period in CZ: 6.2479 years
Tidal index in CZ: 0.025617
Angular size of star in sky in CZ: 0.283921 degrees


Component B1:
Catalog numbers:
     Henry Draper (HD) 60178, Smithsonian Astrophysical Observatory (SAO) 60198, Fifth Fundamental Catalogue (FK5) 287, Hoffleit Bright Star (HR) 2890
Proper motion: 0.198 arcsec/yr (238.9° from north)
Radial Velocity: -1.2 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -4.12, -3.73, -13.8
Spectral class: A5m
Luminosity Class: V
Apparent visual magnitude: +3.60
Absolute visual magnitude: +2.61
Visual luminosity: 7.90 x Sol
Mass: 1.7 x Sol
Diameter: 1.61 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 2.81 A.U.s
Orbital period in CZ: 3.61419 years
Tidal index in CZ: 0.076556
Angular size of star in sky in CZ: 0.306073 degrees


Component B2:
Catalog numbers:
     Henry Draper (HD) 60178, Smithsonian Astrophysical Observatory (SAO) 60198, Fifth Fundamental Catalogue (FK5) 287, Hoffleit Bright Star (HR) 2890
Spectral class: A5m
Luminosity Class: V
Apparent visual magnitude: +3.60
Absolute visual magnitude: +2.61
Visual luminosity: 7.90 x Sol
Mass: 1.7 x Sol
Diameter: 1.61 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 2.81 A.U.s
Orbital period in CZ: 3.61419 years
Tidal index in CZ: 0.076556
Angular size of star in sky in CZ: 0.306073 degrees


Component C1:
Proper names: YY Geminorum
Catalog numbers:
     Bonner Durchmusterung (BD) +321582
Right Ascension and Declination: 7h31m26s, +31°58'47" (epoch 1950.0)
Celestial (X,Y,Z) coordinates in ly: -17.0, 40.3, 27.3
Galactic (X,Y,Z) coordinates in ly: -47.2, -6.19, 19.7
Proper motion: 0.232 arcsec/yr (241.4° from north)
Radial Velocity: -1.9 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -4.39, -3.44, -16.6
Spectral class: M0.5e
Luminosity Class: V
Apparent visual magnitude: +9.82
Absolute visual magnitude: +8.83
Visual luminosity: 0.026 x Sol
Variable type: (E+, E/ ..) (eclipsing binary)
Mass: 0.63 x Sol
Source for mass: Burnham's Celestial Handbook
Diameter: 0.76 x Sol
Source for diameter: Burnham's Celestial Handbook
Comfort Zone (visual): 0.16 A.U.s
Orbital period in CZ: 29.5165 days
Tidal index in CZ: 153.127
Angular size of star in sky in CZ: 2.528531 degrees


Component C2:
Proper names: YY Geminorum
Catalog numbers:
     Bonner Durchmusterung (BD) +321582
Right Ascension and Declination: 7h31m26s, +31°58'47" (epoch 1950.0)
Celestial (X,Y,Z) coordinates in ly: -17.0, 40.3, 27.3
Galactic (X,Y,Z) coordinates in ly: -47.2, -6.19, 19.7
Proper motion: 0.232 arcsec/yr (241.4° from north)
Radial Velocity: -1.9 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -4.39, -3.44, -16.6
Spectral class: M0.5e
Luminosity Class: V
Apparent visual magnitude: +9.82
Absolute visual magnitude: +8.83
Visual luminosity: 0.026 x Sol
Variable type: (E+, E/ ..) (eclipsing binary)
Mass: 0.57 x Sol
Source for mass: Burnham's Celestial Handbook
Diameter: 0.68 x Sol
Source for diameter: Burnham's Celestial Handbook
Comfort Zone (visual): 0.16 A.U.s
Orbital period in CZ: 31.0311 days
Tidal index in CZ: 138.544
Angular size of star in sky in CZ: 2.262370 degrees

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