25 Cancri

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25 Cancri
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cancer
Right ascension  08h 25m 49.87648s[1]
Declination +17° 02′ 46.5632″[1]
Apparent magnitude (V) 6.11[2]
Spectral type F6 V[3]
B−V color index 0.448±0.005[2]
Radial velocity (Rv)+37.38±0.17[1] km/s
Proper motion (μ) RA: −52.104[1] mas/yr
Dec.: −19.683[1] mas/yr
Parallax (π)9.3688 ± 0.2058[1] mas
Distance348 ± 8 ly
(107 ± 2 pc)
Absolute magnitude (MV)2.85[2]
25 Cnc A
Mass1.51[4] M
Luminosity6.60[2] L
Surface gravity (log g)4.01[5] cgs
Temperature6,487[5] K
Metallicity [Fe/H]−0.10[5] dex
Rotational velocity (v sin i)37.74±0.55[6] km/s
Age2.50[5] Gyr
25 Cnc B
Mass0.34[4] M
Other designations
d2 Cnc, 25 Cnc, BD+17°1842, HD 71030, HIP 41319, HR 3299, SAO 97806, WDS 08258+1703[7][8]
Database references

25 Cancri is a common proper motion[4] star system in the zodiac constellation of Cancer, located around 348 light years away from the Sun. It has the Bayer designation d2 Cancri (d2 Cnc); 25 Cancri (25 Cnc) is the Flamsteed designation, it is near the lower limit of visibility to the naked eye in good viewing conditions, appearing as a dim, yellow-white hued star with a combined apparent visual magnitude of 6.11.[2] The pair have a relatively high proper motion, traversing the celestial sphere at an angular rate of 0.245 per year.[9] It is moving further from the Earth with a heliocentric radial velocity of +37 km/s.[1]

Based upon a stellar classification of F6 V,[3] the brighter component is an F-type main-sequence star that is generating energy through hydrogen fusion at its core. Cowley (1976) listed a class of F5 IIIm?,[10] which suggests it may be an Am star. However, this has not been confirmed,[6] it is about 2.5[5] billion years old with 1.51[4] times the mass of the Sun. The star is radiating 6.6[2] times the Sun's luminosity from its photosphere at an effective temperature of 6,487 K.[5]

The companion is 4.19 magnitudes fainter than the primary, and lies at an angular separation of 16.798 along a position angle of 310°, as of 2013.[8] If the pair are gravitationally bound, then they orbit each other with a period of around 4.05 million years.[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 f 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 Harlan, E. A. (September 1969), "MK classifications for F- and G-type stars. I", Astronomical Journal, 74: 916–919, Bibcode:1969AJ.....74..916H, doi:10.1086/110881.
  4. ^ a b c d e Tokovinin, Andrei (2014), "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs", The Astronomical Journal, 147 (4): 87, arXiv:1401.6827, Bibcode:2014AJ....147...87T, doi:10.1088/0004-6256/147/4/87.
  5. ^ a b c d e f Casagrande, L.; et al. (June 2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy and Astrophysics, 530: A138, arXiv:1103.4651, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276.
  6. ^ a b LeBlanc, F.; et al. (November 2015), "Project VeSElkA: results of abundance analysis I - HD 71030, HD 95608, HD 116235 and HD 186568", Monthly Notices of the Royal Astronomical Society, 453 (4): 3766–3771, Bibcode:2015MNRAS.453.3766L, doi:10.1093/mnras/stv1466.
  7. ^ "25 Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-02-25.
  8. ^ a b Riddle, Reed L.; et al. (January 1, 2015), "A Survey of the High Order Multiplicity of Nearby Solar-type Binary Stars with Robo-AO", The Astrophysical Journal, 799: 4, arXiv:1411.0682, Bibcode:2015ApJ...799....4R, doi:10.1088/0004-637X/799/1/4, ISSN 0004-637X
  9. ^ Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal, 129 (3): 1483–1522, arXiv:astro-ph/0412070, Bibcode:2005AJ....129.1483L, doi:10.1086/427854.
  10. ^ Cowley, A. P. (April 1976), "Spectral classification of the bright F stars", Publications of the Astronomical Society of the Pacific, 88: 95–110, Bibcode:1976PASP...88...95C, doi:10.1086/129905.