i Boötis

Proper names: i Boötis, 44 Boötis, i Bootis, 44 Bootis
Catalog numbers:
Gliese (Gl) 575, Henry Draper (HD) 133640, Bonner Durchmusterung (BD) +48°2259, Hipparcos Input Catalog (HIC) 73695, Smithsonian Astrophysical Observatory (SAO) 45357, Aitken Double Star (ADS) 9494, Hoffleit Bright Star (HR) 5618, Struve (STF) 1909
Arity: trinary
Right Ascension and Declination: 15h3m47.534s, +47°39'15.15" (epoch 2000.0)
Distance from Sol: 41.6 light-years (12.8 parsecs)
Standard error in distance: 1.2969%
Source for distance: Hipparcos
Celestial (X,Y,Z) coordinates in ly: -19.5, -20.1, 30.8
Galactic (X,Y,Z) coordinates in ly: 4.02, 22.4, 34.9
Proper motion: 0.396 arcsec/yr (273.8° from north)
Radial Velocity: -29.7 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -17.5, -31.1, -13.5

What do all these fields mean?

Data for A and (Ba-Bb)'s orbit around one other:
Combined absolute visual magnitude: +4.23
Combined visual luminosity: 1.78 x Sol
Period: 225 years
Semimajor Axis: 48.1 A.U.s
Eccentricity: 0.43
Periastron distance: 27.4 A.U.s
Apastron distance: 68.8 A.U.s
Year in which periastron occurs: 2021
Source for orbit data: W.D. Heintz
As seen from A:
     At periastron, (Ba-Bb) would appear as magnitude -18.95
     At apastron, (Ba-Bb) would appear as magnitude -16.95
As seen from (Ba-Bb):
     At periastron, A would appear as magnitude -19.72
     At apastron, A would appear as magnitude -17.72

Data for Ba and Bb's orbit around one other:
Combined apparent visual magnitude: +5.96
Combined absolute visual magnitude: +5.43
Combined visual luminosity: 0.59 x Sol
Period: 6.426968 hours
Semimajor Axis: 0.008 A.U.s
Eccentricity: 0
Periastron distance: 0.008 A.U.s
Apastron distance: 0.008 A.U.s
Source for orbit data: Burnham's Celestial Handbook
Comfort Zone (visual) around both: 0.77 A.U.s

Component A:
Spectral class: F9n
Luminosity Class: V
Apparent visual magnitude: +5.19
Absolute visual magnitude: +4.66
Visual luminosity: 1.19 x Sol
Diameter: 1.92 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)
Comfort Zone (visual): 1.09 A.U.s
Angular size of star in sky in CZ: 0.938100 degrees

Component Ba:
Proper motion: 0.396 arcsec/yr (273.8° from north)
Radial Velocity: 3.4 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -14.3, -13.3, 14.2
Spectral class: G2
Luminosity Class: V
Diameter: 0.89 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)

Component Bb:
Proper motion: 0.396 arcsec/yr (273.8° from north)
Radial Velocity: 3.4 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: -14.3, -13.3, 14.2
Spectral class: G2
Luminosity Class: V
Diameter: 0.89 x Sol
Source for diameter: Apparent Diameters and Absolute Radii of Stars (Fracassini+ 1988)

Data for this star system were most recently updated on 4-April-2001.