Gliese 581

light-years
Proper names: HO Librae
Catalog numbers:
     Gliese (Gl) 581, Bonner Durchmusterung (BD) -7°4003, Giclas (G) 151-46, Luyten Half-Second (LHS) 394, Hipparcos Input Catalog (HIC) 74995, Vyssotsky McCormick (McC) 159, New Suspected Variable (NSV) 7023, Wolf 562
Heavy element abundance: 51% of Sol
Standard error in heavy element abundance: 8%
Arity: singular
Right Ascension and Declination: 15h19m26.863s, -7°43'23.12" (epoch 2000.0)
Distance from Sol: 20.4 light-years (6.27 parsecs)
Standard error in distance: 1.4031%
Source for distance: Hipparcos
Celestial (X,Y,Z) coordinates in ly: -13.1, -15.5, -2.75
Galactic (X,Y,Z) coordinates in ly: 15.7, -1.50, 13.0
Proper motion: 1.224 arcsec/yr (256.3° from north)
Radial Velocity: -9.4 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -22.0, -29.3, 8.44

What do all these fields mean?


Spectral class: M2.5
Luminosity Class: V
Apparent visual magnitude: +10.57 (increasing to +10.56)
Absolute visual magnitude: +11.58 (increasing to +11.58)
Visual luminosity: 0.0020 x Sol (increasing to 0.0020 x Sol)
Variable type: UV Ceti flare star (eruptive variable)
Color indices: B-V= +1.60, U-B= +1.23, R-I= +1.10
Mass: 0.31 x Sol
Diameter: 0.38 x Sol
Comfort Zone (visual): 0.045 A.U.s
Orbital period in CZ: 6.26452 days
Tidal index in CZ: 3399.42
Angular size of star in sky in CZ: 4.500722 degrees
Detected companions: 3
Companion b:
     Mass: 0.049 x Jupiter, minimum
     Period: 5.4 days
     Semimajor Axis: 0.041 A.U.s
     Eccentricity: 0.02
     Periastron distance: 0.04018 A.U.s
     Apastron distance: 0.04182 A.U.s
Companion c:
     Mass: 0.016 x Jupiter, minimum
     Diameter: 0.14 x Jupiter
     Period: 12.9 days
     Semimajor Axis: 0.073 A.U.s
     Eccentricity: 0.16
     Periastron distance: 0.06132 A.U.s
     Apastron distance: 0.08468 A.U.s
Companion d:
     Mass: 0.024 x Jupiter, minimum
     Period: 83.6 days
     Semimajor Axis: 0.25 A.U.s
     Eccentricity: 0.2
     Periastron distance: 0.2 A.U.s
     Apastron distance: 0.3 A.U.s

light-years
but not more than light-years away
Data for this star system were most recently updated on 26-April-2007.