HD 34790

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HD 34790
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga
Right ascension  05h 21m 12.68806s[1]
Declination +29° 34′ 11.5926″[1]
Apparent magnitude (V) 5.66[2]
Spectral type A1Vs[3]
U−B color index +0.13[4]
B−V color index +0.06[4]
Radial velocity (Rv)−18.7±0.9[5] km/s
Proper motion (μ) RA: −0.40[1] mas/yr
Dec.: +0.91[1] mas/yr
Parallax (π)11.29 ± 0.32 mas
Distance289 ± 8 ly
(89 ± 3 pc)
Period (P)2.1517 d
Eccentricity (e)0.0
Periastron epoch (T)21140.396
Luminosity35[7] L
Temperature8,682[7] K
Rotational velocity (v sin i)52[8] km/s
Other designations
BD+29° 869, HD 34790, HIP 25001, HR 1752, SAO 77124.
Database references

HD 34790 is a double-lined spectroscopic binary[9] star system in the northern constellation of Auriga. It has a combined apparent magnitude of 5.66,[2] which means it is faintly visible to the naked eye. Based upon observations by the Hipparcos satellite, it is located around 289 light years away,[1] it has a combined stellar classification of A1Vs,[3] matching that of an A-type main sequence star, and shines with 35 times the luminosity of the Sun.[7]

The two stars orbit each other with a period of only 2.15 days and an eccentricity of zero, indicating their orbit is close to circular.[6] They are orbiting sufficiently close to each other that their rotation periods have most likely become tidally locked—meaning they always maintain the same face toward each other.[9]


  1. ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357
  2. ^ a b Oja, T. (August 1991), "UBV photometry of stars whose positions are accurately known. VI", Astronomy and Astrophysics Supplement Series, 89 (2): 415–419, Bibcode:1991A&AS...89..415O
  3. ^ a b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819
  4. ^ a b Osawa, K.; Hata, S. (1962), "Three-color photometry of B8-A2 stars (II).", Annals of the Tokyo Astronomical Observatory, 7: 209, Bibcode:1962AnTok...7..209O
  5. ^ Wilson, R. E. (1953), General Catalogue of Stellar Radial Velocities, Carnegie Institute of Washington, D.C., Bibcode:1953GCRV..C......0W
  6. ^ a b Pourbaix, D.; et al. (September 2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy and Astrophysics, 424: 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213
  7. ^ a b c McDonald, I.; et al. (2012). "Fundamental Parameters and Infrared Excesses of Hipparcos Stars". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–57. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x.
  8. ^ Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224
  9. ^ a b Abt, Helmut A.; Boonyarak, Chayan (November 2004), "Tidal Effects in Binaries of Various Periods", The Astrophysical Journal, 616 (1): 562–566, Bibcode:2004ApJ...616..562A, doi:10.1086/423795

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