Upsilon Geminorum

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υ Geminorum
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Gemini
Right ascension 07h 35m 55.34970s[1]
Declination +26° 53′ 44.6751″[1]
Apparent magnitude (V) 4.04[2] (4.04 - 4.08[3])
Spectral type M0 III[4]
U−B color index +1.96[2]
B−V color index +1.54[2]
Variable type suspected[3]
Radial velocity (Rv) −21.61±0.19[5] km/s
Proper motion (μ) RA: −34.12[1] mas/yr
Dec.: -106.96[1] mas/yr
Parallax (π) 12.04 ± 0.68[1] mas
Distance 270 ± 20 ly
(83 ± 5 pc)
Mass 1.52[6] M
Radius 44[5] R
Luminosity 417[5] L
Surface gravity (log g) 1.0[5] cgs
Temperature 3,926±16[5] K
Metallicity [Fe/H] 0.17[6] dex
Rotational velocity (v sin i) 5.9[5] km/s
Age 3.53[6] Gyr
Other designations
υ Gem, 69 Geminorum, BD+27° 1424, FK5 1196, HD 60522, HIP 36962, HR 2905, SAO 79533.[7]
Database references

Upsilon Geminorum (υ Gem) is a star in the constellation Gemini. It has an apparent visual magnitude of 4.04,[2] which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 12.04 mas,[1] it is around 270 light years from the Sun. There is a visual companion: a magnitude 13.20 star located at an angular separation of 55.20 along a position angle of 40°, as of 2008.[8]

This is a evolved red giant star with a stellar classification of M0 III.[4] It is estimated to have 1.52[6] times the mass of the Sun, but has expanded to 44[5] times the Sun's radius. The star is spinning with a projected rotational velocity of 5.9 km/s[5] and is about 3.53[6] billion years old. Upsilon Geminorum is radiating 417 times the solar luminosity from its outer atmosphere at an effective temperature of 3926 K.[5]

Based upon the motion of this star through space, Upsilon Geminorum is a member of the Wolf 630 moving group. This is a set of stars centered on Wolf 630 that are moving nearly in parallel and have an age of around 2.7±0.5 billion years. They may be former members of a dissolved open cluster.[9]


  1. ^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752Freely accessible, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV data, SIMBAD, Bibcode:1986EgUBV........0M. 
  3. ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S. 
  4. ^ a b Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics, 11: 29, Bibcode:1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333. 
  5. ^ a b c d e f g h i Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209. 
  6. ^ a b c d e Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 23, Bibcode:2015AJ....150...88L, arXiv:1507.01466Freely accessible, doi:10.1088/0004-6256/150/3/88, 88. 
  7. ^ "ups Gem -- Variable Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-12-08. 
  8. ^ Mason, B. D.; et al. (2014), The Washington Visual Double Star Catalog, Bibcode:2001AJ....122.3466M, doi:10.1086/323920. 
  9. ^ Bubar, Eric J.; King, Jeremy R. (August 2010), "Spectroscopic Abundances and Membership in the Wolf 630 Moving Group", The Astronomical Journal, 140 (2): 293−318, Bibcode:2010AJ....140..293B, arXiv:1005.1205Freely accessible, doi:10.1088/0004-6256/140/2/293. 

External links[edit]

  • Kaler, James B. (March 2, 2012), "Upsilon Geminorum", Stars, University of Illinois, retrieved 2016-12-08.