Nu Geminorum

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ν Geminorum
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Gemini
Right ascension 06h 28m 57.78613s[1]
Declination +20° 12′ 43.6856″[1]
Apparent magnitude (V) 4.16[2]
Spectral type B6 III + B8 III[3]
U−B color index −0.47[2]
B−V color index −0.13[2]
Radial velocity (Rv)+39.4[4] km/s
Proper motion (μ) RA: −6.82[1] mas/yr
Dec.: −13.10[1] mas/yr
Parallax (π)5.99 ± 0.28[1] mas
Distance540 ± 30 ly
(167 ± 8 pc)
Absolute magnitude (MV)−2.2 + −1.2[3]
Period (P)18.75±0.34 yr
Semi-major axis (a)0.081±0.008
Eccentricity (e)0.297±0.049
Inclination (i)72.9±1.4°
Longitude of the node (Ω)120.9±1.1°
Periastron epoch (T)1992.57±0.18
Argument of periastron (ω)
ν Gem Aa
Mass6.4[3] M
Luminosity1,380[5] L
Temperature14,100[5] K
Rotational velocity (v sin i)160[6] km/s
ν Gem Ab
Mass4.6[3] M
Other designations
ν Gem, 18 Geminorum, BD++20° 1441, FK5 1173, HD 45542, HIP 30883, HR 2343, SAO 78423, WDS J06290+2013.[7]
Database references

Nu Geminorum (ν Gem) is a binary, and possibly a multiple[3] star system in the constellation Gemini. It has an apparent visual magnitude of 4.16,[2] which is bright enough to be visible to the naked eye on a dark night. Based upon an annual parallax shift of 5.99 mas,[1] it is located at a distance of roughly 540 light years from the Sun.

The main components of this potentially multiple star system have an orbital period of 18.75 years and an eccentricity of 0.297.[3] There is much uncertainty in the spectral type, with classifications ranging from a main sequence star to a giant. The spectra indicate the presence of a Be star in the system.[8]


  1. ^ a b c d e f van Leeuwen, F. (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 Crawford, D. L.; et al. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere", The Astronomical Journal, 76: 1058, Bibcode:1971AJ.....76.1058C, doi:10.1086/111220. 
  3. ^ a b c d e f g Cvetković, Z.; Ninković, S. (November 2008), "Orbits for two short-period and two long-period binaries", New Astronomy, 13 (8): 587–592, Bibcode:2008NewA...13..587C, doi:10.1016/j.newast.2008.03.005. 
  4. ^ Wilson, R. E. (1953), General Catalogue of Stellar Radial Velocities, Carnegie Institute of Washington D.C., Bibcode:1953GCRV..C......0W. 
  5. ^ a b Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335Freely accessible, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355. 
  6. ^ Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590. 
  7. ^ "nu. Gem". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-12-06. 
  8. ^ Silaj, J.; et al. (November 2014), "The Hα Profiles of Be Shell Stars", The Astrophysical Journal, 795 (1): 12, Bibcode:2014ApJ...795...82S, doi:10.1088/0004-637X/795/1/82, 82. 

External links[edit]

  • Kaler, James B. (January 26, 2007), "Nu Geminorum", stars, University of Illinois, retrieved 2016-12-07.