Antares

light-years
Proper names: Antares, Alpha Scorpii, Cor Scorpionis, 21 Scorpii
Catalog numbers:
     Henry Draper (HD) 148478, Cordoba Durchmusterung (CD) -26°11359, Hoffleit Bright Star (HR) 6134, Aitken Double Star (ADS) 10074, Smithsonian Astrophysical Observatory (SAO) 184415, Fifth Fundamental Catalogue (FK5) 616, Cape Photographic Durchmusterung (CPD) -26°5648, Hipparcos Input Catalog (HIC) 80763, Caltech 2-microns Survey (IRC) -30265
Arity: binary
Points of interest:
     The A star is actually egg-shaped, and is only about two-thirds as tall as it is wide.  The "diameter" listed below is measured across its widest chord.
     Both stars are enveloped in a reddish nebula some 5 light-years in diameter, probably composed of metallic dust.

Right Ascension and Declination: 16h29m24.439s, -26°25'55.15" (epoch 2000.0)
Distance from Sol: 604 light-years (185 parsecs)
Standard error in distance: 23.7288%
Source for distance: Hipparcos
Celestial (X,Y,Z) coordinates in ly: -208, -499, -269
Galactic (X,Y,Z) coordinates in ly: 579, -78, 151
Proper motion: 0.0224 arcsec/yr (243.4° from north)
Radial Velocity: -1.4 km/sec
Source for proper motion: Hipparcos Input Catalog
Source for radial velocity: Burnham's Celestial Handbook
Galactic (U,V,W) velocity components in km/s: -5.6, -18, 6.8

What do all these fields mean?

Data for A and B's orbit around one other:
Combined absolute visual magnitude: -5.16
Combined visual luminosity: 10069 x Sol
Period: 878 years
Semimajor Axis: 537 A.U.s
Eccentricity: 0.1
Periastron distance: 483 A.U.s
Apastron distance: 590 A.U.s
Year in which periastron occurs: 1461
Source for orbit data: P. Baize
As seen from A:
     At periastron, B would appear as magnitude -18.99
     At apastron, B would appear as magnitude -18.55
As seen from B:
     At periastron, A would appear as magnitude -23.29
     At apastron, A would appear as magnitude -22.85


Component A:
Spectral class: M1
Luminosity Class: Ib
Apparent visual magnitude: +1.20 (increasing to +0.90)
Absolute visual magnitude: -5.14 (increasing to -5.44)
Visual luminosity: 9880 x Sol (increasing to 13025 x Sol)
Variable type: slow irregular (pulsating variable)
Color indices: B-V= +1.93
Mass: 12 x Sol
Source for mass: Burnham's Celestial Handbook
Diameter: 796 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 99 A.U.s
Orbital period in CZ: 286.079 years
Tidal index in CZ: 0.000012
Angular size of star in sky in CZ: 4.266630 degrees


Component B:
Spectral class: B4
Luminosity Class: V-VI
Apparent visual magnitude: +5.50
Absolute visual magnitude: -0.84
Visual luminosity: 188 x Sol
Mass: 3 x Sol
Comfort Zone (visual): 14 A.U.s
Orbital period in CZ: 29.3395 years
Tidal index in CZ: 0.001162

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