Regulus

light-years
Proper names: Regulus, Alpha Leonis, 11 Leonis, Cor Leonis
Catalog numbers:
     Henry Draper (HD) 87901, Bonner Durchmusterung (BD) +12°2149, Aitken Double Star (ADS) 7654, Hoffleit Bright Star (HR) 3982, Smithsonian Astrophysical Observatory (SAO) 98967, Fifth Fundamental Catalogue (FK5) 380, Hipparcos Input Catalog (HIC) 49669, New Suspected Variable (NSV) 4750, Woolley (Wo) 9316
Age: less than 300 million years
Arity: trinary
Right Ascension and Declination: 10h8m22.315s, +11°58'1.89" (epoch 2000.0)
Distance from Sol: 77.5 light-years (23.8 parsecs)
Standard error in distance: 1.8424%
Source for distance: Hipparcos
Celestial (X,Y,Z) coordinates in ly: -67.0, 35.5, 16.1
Galactic (X,Y,Z) coordinates in ly: -34.2, -37.0, 58.8
Proper motion: 0.25 arcsec/yr (270.0° from north)
Radial Velocity: 5.9 km/sec
Source for proper motion: Burnham's Celestial Handbook
Source for radial velocity: Hipparcos Input Catalog
Galactic (U,V,W) velocity components in km/s: -25.2, -7.53, -11.6

What do all these fields mean?

Data for A and (B-C)'s orbit around one other:
Combined absolute visual magnitude: -0.52
Combined visual luminosity: 141 x Sol
Observed Separation: 4205 A.U.s
Source for orbit data: Burnham's Celestial Handbook
As seen from A:
     (B-C) would appear as magnitude -7.34
As seen from (B-C):
     A would appear as magnitude -13.97

Data for B and C's orbit around one other:
Combined absolute visual magnitude: +6.11
Combined visual luminosity: 0.31 x Sol
Observed Separation: 92.7 A.U.s
Year of separation observation: 1867
Source for orbit data: Burnham's Celestial Handbook
As seen from B:
     C would appear as magnitude -10.62
As seen from C:
     B would appear as magnitude -15.62

Data for B and C's orbit, take 2:
Observed Separation: 61.8 A.U.s
Year of separation observation: 1978
Source for orbit data: Burnham's Celestial Handbook
As seen from B:
     C would appear as magnitude -11.50
As seen from C:
     B would appear as magnitude -16.50


Component A:
Spectral class: B7
Luminosity Class: V
Apparent visual magnitude: +1.36
Absolute visual magnitude: -0.52
Visual luminosity: 141 x Sol
Color indices: B-V= -0.87
Mass: 4.4 x Sol
Diameter: 3.50 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 11.9 A.U.s
Orbital period in CZ: 19.4574 years
Tidal index in CZ: 0.002641
Angular size of star in sky in CZ: 0.157323 degrees


Component B:
Spectral class: K1
Luminosity Class: V
Apparent visual magnitude: +8.00
Absolute visual magnitude: +6.12
Visual luminosity: 0.31 x Sol
Mass: 0.8 x Sol
Comfort Zone (visual): 0.56 A.U.s
Orbital period in CZ: 169.73 days
Tidal index in CZ: 4.63089


Component C:
Spectral class: M
Luminosity Class: V
Apparent visual magnitude: +13.00
Absolute visual magnitude: +11.12
Visual luminosity: 0.0031 x Sol
Mass: 0.2 x Sol
Comfort Zone (visual): 0.056 A.U.s
Orbital period in CZ: 10.7328 days
Tidal index in CZ: 1158.11

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