Harvard Observatory 305

light-years

Catalog numbers:
     Gliese (Gl) 818.1, Henry Draper (HD) 200525, Cape Photographic Durchmusterung (CPD) -73°2192, Luyten Half-Second (LHS) 3635, Hipparcos Input Catalog (HIC) 104440, Smithsonian Astrophysical Observatory (SAO) 257890, Hoffleit Bright Star (HR) 8061, Harvard Observatory (HDO) 305, Woolley (Wo) 9719
Arity: trinary
Right Ascension and Declination: 21h9m22.24s, -73°10'22.9" (epoch 2000.0)
Distance from Sol: 61.1 light-years (18.7 parsecs)
Standard error in distance: 3.9237%
Source for distance: Hipparcos
Celestial (X,Y,Z) coordinates in ly: 13.0, -12.0, -58.5
Galactic (X,Y,Z) coordinates in ly: 37.9, -31.7, -35.9
Proper motion: 0.55 arcsec/yr (127.6° from north)
Radial Velocity: -10.1 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -44.1, -20.1, -11.6

What do all these fields mean?

Data for A and B's orbit around one other:
Combined absolute visual magnitude: +4.28
Combined visual luminosity: 1.68 x Sol
Observed Separation: 3.75 A.U.s
As seen from A:
     B would appear as magnitude -23.67
As seen from B:
     A would appear as magnitude -23.67

Data for (A-B) and C's orbit around one other:
Combined spectrum: G3 IV
Combined absolute visual magnitude: +4.28
Combined visual luminosity: 1.68 x Sol
Observed Separation: 152 A.U.s
Year of separation observation: 1901
As seen from (A-B):
     C would appear as magnitude -8.53
As seen from C:
     (A-B) would appear as magnitude -16.38

Data for (A-B) and C's orbit, take 2:
Observed Separation: 148 A.U.s
Year of separation observation: 1931
As seen from (A-B):
     C would appear as magnitude -8.58
As seen from C:
     (A-B) would appear as magnitude -16.44


Component A:
Apparent visual magnitude: +6.40
Absolute visual magnitude: +5.04
Visual luminosity: 0.84 x Sol
Diameter: 1.41 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 0.92 A.U.s
Angular size of star in sky in CZ: 0.819251 degrees


Component B:
Apparent visual magnitude: +6.40
Absolute visual magnitude: +5.04
Visual luminosity: 0.84 x Sol
Comfort Zone (visual): 0.92 A.U.s


Component C:
Apparent visual magnitude: +13.50
Absolute visual magnitude: +12.14
Visual luminosity: 0.0012 x Sol
Diameter: 0.35 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 0.035 A.U.s
Angular size of star in sky in CZ: 5.349778 degrees

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