Sigma2 Cancri

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Sigma2 Cancri
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cancer
Right ascension  08h 56m 56.59711s[1]
Declination +32° 54′ 37.5423″[1]
Apparent magnitude (V) +5.436[2]
Spectral type A7 IV[3]
B−V color index +0.157[2]
Radial velocity (Rv)−26.2±0.7[4] km/s
Proper motion (μ) RA: −53.49[1] mas/yr
Dec.: −66.13[1] mas/yr
Parallax (π)16.79 ± 0.29[1] mas
Distance194 ± 3 ly
(60 ± 1 pc)
Absolute magnitude (MV)+1.57[5]
Mass1.79[6] M
Luminosity21.5[3] L
Surface gravity (log g)4.17[6] cgs
Temperature8,309±283[6] K
Rotational velocity (v sin i)133[3] km/s
Age441[6] Myr
Other designations
σ2 Cnc, 59 Cancri, BD+33° 1785, HD 76398, HIP 43932, HR 3555, SAO 61146[7]
Database references

Sigma2 Cancri, Latinized from σ2 Cancri, is the Bayer designation for a solitary,[8] white-hued star in the constellation Cancer. It is faintly visible to the naked eye, with an apparent visual magnitude of +5.44.[2] Based upon an annual parallax shift of 16.79 mas as seen from Earth,[1] this star is located around 194 light years from the Sun.

With an estimated age of 441[6] million years, this is an A-type subgiant star with a stellar classification of A7 IV.[3] It is spinning relatively rapidly with a projected rotational velocity of 133 K.[3] The star has an estimated 1.8[6] times the mass of the Sun and is radiating 21.5[3] times the Sun's luminosity from its photosphere at an effective temperature of roughly 8,309 K.[6]


  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 Høg, E.; et al. (March 2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy and Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H, doi:10.1888/0333750888/2862.
  3. ^ a b c d e f Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691.
  4. ^ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  5. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  6. ^ a b c d e f g David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146.
  7. ^ "sig02 Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-12.
  8. ^ 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.