Tau Boötis

light-years
Proper names: Tau Boötis, 4 Boötis, Tau Bootis, 4 Bootis
Catalog numbers:
     Gliese (Gl) 527, Henry Draper (HD) 120136, Bonner Durchmusterung (BD) +18°2782, Hipparcos Input Catalog (HIC) 67275, Smithsonian Astrophysical Observatory (SAO) 100706, Aitken Double Star (ADS) 9025, Fifth Fundamental Catalogue (FK5) 507, Hoffleit Bright Star (HR) 5185, New Suspected Variable (NSV) 6444, Luyten Two-Tenth (LTT) 14021
Heavy element abundance: 157% of Sol
Standard error in heavy element abundance: 14%
Source for heavy element abundance: Strobel [Fe/H] Determinations
Arity: the A star is a possible spectroscopic binary
Right Ascension and Declination: 13h47m15.74s, +17°27'24.43" (epoch 2000.0)
Distance from Sol: 50.9 light-years (15.6 parsecs)
Standard error in distance: 1.0799%
Source for distance: Hipparcos
Celestial (X,Y,Z) coordinates in ly: -43.3, -21.9, 15.3
Galactic (X,Y,Z) coordinates in ly: 14.6, -0.12, 48.7
Proper motion: 0.483 arcsec/yr (274.4° from north)
Radial Velocity: -16.1 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -32.9, -20.0, -6.97

What do all these fields mean?

Data for A and B's orbit around one other:
Combined absolute visual magnitude: +3.53
Combined visual luminosity: 3.37 x Sol
Observed Separation: 240 A.U.s
Source for orbit data: http://cfa-www.harvard.edu/planets/tau-Boo.html
As seen from A:
     B would appear as magnitude -9.64
As seen from B:
     A would appear as magnitude -16.14


Component A:
Spectral class: F7
Luminosity Class: V
Apparent visual magnitude: +4.50
Absolute visual magnitude: +3.53
Visual luminosity: 3.36 x Sol
Color indices: B-V= +0.48, U-B= +0.04, R-I= +0.15
Mass: 1.3 x Sol
Diameter: 1.68 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 1.83 A.U.s
Orbital period in CZ: 2.17549 years
Tidal index in CZ: 0.211292
Angular size of star in sky in CZ: 0.487652 degrees
Detected companions: 1
Companion b:
     Mass: 3.9 x Jupiter, minimum
     Period: 3.3124 days
     Standard Error in period: 0.0121%
     Semimajor Axis: 0.046 A.U.s
     Source for orbit data: Marcy & Butler


Component B:
Spectral class: M2
Luminosity Class: V
Apparent visual magnitude: +11.00
Absolute visual magnitude: +10.03
Visual luminosity: 0.0084 x Sol
Mass: 0.2 x Sol
Diameter: 0.58 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 0.092 A.U.s
Orbital period in CZ: 22.7253 days
Tidal index in CZ: 258.322
Angular size of star in sky in CZ: 3.367361 degrees

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