3 Cancri

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3 Cancri
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cancer
Right ascension  08h 00m 47.30744s[1]
Declination +17° 18′ 31.3283″[1]
Apparent magnitude (V) 5.60[2]
Spectral type K3 III[3]
B−V color index 1.317[4]
Radial velocity (Rv)+39.55±0.16[1] km/s
Proper motion (μ) RA: −10.403[1] mas/yr
Dec.: −3.905[1] mas/yr
Parallax (π)4.0087 ± 0.1511[1] mas
Distance810 ± 30 ly
(249 ± 9 pc)
Absolute magnitude (MV)−1.29[2]
Mass2.9[5] M
Radius40[5] R
Luminosity568.61[2] L
Surface gravity (log g)2.05[4] cgs
Temperature4,300[4] K
Rotational velocity (v sin i)5.73[4] km/s
Other designations
3 Cnc, BD+17°1731, FK5 2618, HD 65759, HIP 39177, HR 3128, SAO 97472[6]
Database references

3 Cancri is a single[7] star in the zodiac constellation of Cancer, located around 810 light years from the Sun. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.60.[2] This object is moving further from the Earth with a heliocentric radial velocity of +39.5 km/s,[1] and may be a member of the Hyades group.[8] It is located near the ecliptic and thus is subject to lunar eclipses.[9]

This is an aging giant star with a stellar classification of K3 III[3] that is most likely (86% chance) on the horizontal branch.[5] The star has 2.9 times the mass of the Sun and has expanded to 40 times the Sun's radius.[5] It is radiating 569[2] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,300 K.[4]


  1. ^ a b c d e f g Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c d e 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.
  3. ^ a b Adams, Walter S.; et al. (1935), "The Spectroscopic Absolute Magnitudes and Parallaxes of 4179 Stars", Astrophysical Journal, 81: 187, Bibcode:1935ApJ....81..187A, doi:10.1086/143628
  4. ^ a b c d e Hekker, S.; Meléndez, J. (2007), "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters", Astronomy and Astrophysics, 475 (3): 1003–1009, arXiv:0709.1145, Bibcode:2007A&A...475.1003H, doi:10.1051/0004-6361:20078233.
  5. ^ a b c d Stock, S.; et al. (August 2018), "Precise radial velocities of giant stars. X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search", Astronomy & Astrophysics, 616: 15, arXiv:0709.1145, Bibcode:2018A&A...616A..33S, doi:10.1051/0004-6361/201833111, A33.
  6. ^ "3 Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-02-22.
  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, O. J. (June 1972), "The red giants in the Hyades group", Publications of the Astronomical Society of the Pacific, 84: 406, Bibcode:1972PASP...84..406E, doi:10.1086/129303.
  9. ^ White, Nathaniel M.; Feierman, Barry H. (September 1987), "A Catalog of Stellar Angular Diameters Measured by Lunar Occultation", Astronomical Journal, 94: 751, Bibcode:1987AJ.....94..751W, doi:10.1086/114513.