Kappa Arietis

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Kappa Arietis
Diagram showing star positions and boundaries of the Aries constellation and its surroundings
Cercle rouge 100%.svg
Location of κ Arietis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Aries
Right ascension 02h 06m 33.92388s[1]
Declination +22° 38′ 53.9267″[1]
Apparent magnitude (V) 5.02[2]
Spectral type A2m[3]
U−B color index +0.11[2]
B−V color index +0.12[2]
Radial velocity (Rv)+11.5[4] km/s
Proper motion (μ) RA: +17.86[1] mas/yr
Dec.: –37.55[1] mas/yr
Parallax (π)17.96 ± 0.37 mas
Distance182 ± 4 ly
(56 ± 1 pc)
Absolute magnitude (MV)1.30[3]
Luminosity25[3] L
Surface gravity (log g)4.0[5] cgs
Temperature8,700[5] K
Metallicity [Fe/H]+0.18[5] dex
Rotational velocity (v sin i)18[6] km/s
Other designations
κ Ari, 12 Arietis, BD+21 279, HD 12869, HIP 9836, HR 613, SAO 75146[7]
Database references

Kappa Arietis, Latinized from κ Arietis, is the Bayer designation for a binary star in the northern constellation of Aries. It is approximately 182 light-years (56 parsecs) distant from Earth. The combined apparent visual magnitude of the pair is 5.02,[2] making the system bright enough for it to be dimly visible to the naked eye. Kappa Arietis is a double-lined spectroscopic binary with both components displaying the spectral properties of an Am, or metallic-lined star. They have nearly the same brightness and their mass ratio is 1.03; very close to equal.[5] Their orbital period is 15.2938 days and they have a high eccentricity of 0.61.[8]


  1. ^ a b c d van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Mendoza, E. E.; Gomez, V. T.; Gonzalez, S. (June 1978), "UBVRI photometry of 225 AM stars", Astronomical Journal, 83: 606–614, Bibcode:1978AJ.....83..606M, doi:10.1086/112242. 
  3. ^ a b c Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971Freely accessible, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. 
  4. ^ Wilson, Ralph Elmer (1953), General Catalogue of Stellar Radial Velocities, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W. 
  5. ^ a b c d Mitton, J. (January 1977), "Spectroscopic observations and curve-of-growth analyses of the four A stars omicron Peg, beta Ari, kappa Ari and 32 Vir", Astronomy and Astrophysics Supplement Series, 27: 35–46, Bibcode:1977A&AS...27...35M. 
  6. ^ Royer, F.; et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics, 393: 897–911, arXiv:astro-ph/0205255Freely accessible, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943. 
  7. ^ "kap Ari -- Variable Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-08-04. 
  8. ^ Abt, Helmut A. (August 2005), "Observed Orbital Eccentricities", The Astrophysical Journal, 629 (1): 507–511, Bibcode:2005ApJ...629..507A, doi:10.1086/431207. 

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