Tau Ophiuchi

light-years
Proper names: Tau Ophiuchi, 69 Ophiuchi
Catalog numbers:
     Gliese (Gl) 700.1, Bonner Durchmusterung (BD) -8°4549, Hipparcos Input Catalog (HIC) 88404, Smithsonian Astrophysical Observatory (SAO) 142050, Aitken Double Star (ADS) 11005, Struve (STF) 2262, Woolley (Wo) 9612
Heavy element abundance: 117% of Sol
Source for heavy element abundance: Strobel [Fe/H] Determinations
Arity: trinary
Right Ascension and Declination: 18h3m4.96s, -8°10'49.36" (epoch 2000.0)
Distance from Sol: 56 light-years (17 parsecs)
Standard error in distance: 13.5015%
Source for distance: Gliese
Celestial (X,Y,Z) coordinates in ly: 0.7, -55, -8.0
Galactic (X,Y,Z) coordinates in ly: 52, 19, 6.1
Proper motion: 0.046 arcsec/yr (147.1° from north)
Radial Velocity: -38.4 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -35, -15, -7.5

What do all these fields mean?

Data for A and B's orbit around one other:
Combined spectrum: F3 V
Combined absolute visual magnitude: +3.61
Combined visual luminosity: 3.1 x Sol
Period: 280.03 years
Semimajor Axis: 26 A.U.s
Eccentricity: 0.718
Periastron distance: 7.2 A.U.s
Apastron distance: 44 A.U.s
Year in which periastron occurs: 1829
Source for orbit data: S. Wierzbinski
As seen from A:
     At periastron, B would appear as magnitude -22.52
     At apastron, B would appear as magnitude -18.60
As seen from B:
     At periastron, A would appear as magnitude -23.21
     At apastron, A would appear as magnitude -19.29

Data for (A-B) and C's orbit around one other:
Combined absolute visual magnitude: +3.59
Combined visual luminosity: 3.2 x Sol
Observed Separation: 1720 A.U.s
Source for orbit data: Gliese
As seen from (A-B):
     C would appear as magnitude -7.17
As seen from C:
     (A-B) would appear as magnitude -11.79


Component A:
NOTE: This star is actually a close-orbiting binary pair. The data below are for both sub-components of the pair combined.
Catalog numbers:
     Henry Draper (HD) 164765, Hoffleit Bright Star (HR) 6734
Apparent visual magnitude: +5.24
Absolute visual magnitude: +4.07
Visual luminosity: 2.1 x Sol
Diameter: 1.05 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 1.4 A.U.s
Angular size of star in sky in CZ: 0.390542 degrees


Component B:
Catalog numbers:
     Henry Draper (HD) 164764, Hoffleit Bright Star (HR) 6733, New Suspected Variable (NSV) 10073
Proper motion: 0.046 arcsec/yr (147.1° from north)
Radial Velocity: -35.1 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -32, -14, -7.1
Apparent visual magnitude: +5.93
Absolute visual magnitude: +4.76
Visual luminosity: 1.1 x Sol
Diameter: 0.97 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 1.0 A.U.s
Angular size of star in sky in CZ: 0.495743 degrees


Component C:
Right Ascension and Declination: 18h0m27s, -8°11'54" (epoch 1950.0)
Celestial (X,Y,Z) coordinates in ly: 0.1, -55, -8.0
Galactic (X,Y,Z) coordinates in ly: 52, 19, 6.7
Proper motion: 0.05 arcsec/yr (147.0° from north)
Radial Velocity: -14 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -12, -6.4, -5.2
Spectral class: M
Luminosity Class: V
Apparent visual magnitude: +9.40
Absolute visual magnitude: +8.23
Visual luminosity: 0.04 x Sol
Diameter: 0.68 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 0.2 A.U.s
Angular size of star in sky in CZ: 1.718020 degrees

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