Sigma3 Cancri

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Sigma3 Cancri
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cancer
Right ascension  08h 59m 32.65432s[1]
Declination +32° 25′ 06.8093″[1]
Apparent magnitude (V) +5.24[2]
Spectral type G9 III[3]
U−B color index +0.64[2]
B−V color index +0.91[2]
Radial velocity (Rv)+20.82±0.21[4] km/s
Proper motion (μ) RA: −43.78[1] mas/yr
Dec.: −35.03[1] mas/yr
Parallax (π)11.03 ± 0.28[1] mas
Distance296 ± 8 ly
(91 ± 2 pc)
Absolute magnitude (MV)0.45[5]
Mass2.81±0.11 M
Radius10.32 R
Luminosity72 L
Surface gravity (log g)3.18 cgs
Temperature5,170±21 K
Metallicity [Fe/H]−0.03±0.06 dex
Rotational velocity (v sin i)2.30±0.47 km/s
Age420±40 Myr
Other designations
σ3 Cnc, 64 Cancri, BD+32° 1821, FK5 1232, HD 76813, HIP 44154, HR 3575, SAO 61177[6]
Database references

Sigma3 Cancri3 Cancri) is a solitary,[7] yellow-hued star in the zodiac constellation of Cancer. With an apparent visual magnitude of +5.24,[2] it is a dim star that is visible to the naked eye. Based upon an annual parallax shift of 11.03 mas as seen from Earth,[1] it is located around 296 light years from the Sun. The star's proper motion makes it a candidate for membership in the IC 2391 supercluster.[8]

This is an evolved, G-type giant star with a stellar classification of G9 III.[3] At the estimated age of 420[4] million years it is a red clump star on the horizontal branch, which indicates it is generating energy through helium fusion at its core.[9] Sigma3 Cancri has 2.8 times the mass of the Sun and has expanded to 10.3 times the Sun's radius. It is radiating 72 times the solar luminosity from its photosphere at an effective temperature of 5,170 K.[4]


  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:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. ^ a b c d Guetter, H. H.; Hewitt, A. V. (1984), "Photoelectric UBV photometry for 317 PZT and VZT stars", Astronomical Society of the Pacific, 96: 441–443, Bibcode:1984PASP...96..441G, doi:10.1086/131362.
  3. ^ a b Sato, K.; Kuji, S. (1990), "MK classification and photometry of stars used for time and latitude observations at Mizusawa and Washington", Astronomy and Astrophysics Supplement Series, 85: 1069, Bibcode:1990A&AS...85.1069S.
  4. ^ a b c d Jofré, E.; et al. (2015), "Stellar parameters and chemical abundances of 223 evolved stars with and without planets", Astronomy & Astrophysics, 574: A50, arXiv:1410.6422, Bibcode:2015A&A...574A..50J, doi:10.1051/0004-6361/201424474.
  5. ^ Da Silva, Ronaldo; et al. (2015), "Homogeneous abundance analysis of FGK dwarf, subgiant, and giant stars with and without giant planets", Astronomy & Astrophysics, 580: A24, arXiv:1505.01726, Bibcode:2015A&A...580A..24D, doi:10.1051/0004-6361/201525770.
  6. ^ "sig03 Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-11.
  7. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  8. ^ Eggen, Olin J. (December 1995), "Reality Tests of Superclusters in the Young Disk Population", Astronomical Journal, 110: 2862, Bibcode:1995AJ....110.2862E, doi:10.1086/117734.
  9. ^ Mishenina, T. V.; et al. (September 2006), "Elemental abundances in the atmosphere of clump giants", Astronomy and Astrophysics, 456 (3): 1109–1120, arXiv:astro-ph/0605615, Bibcode:2006A&A...456.1109M, doi:10.1051/0004-6361:20065141.