Kappa Cancri
Location of κ Cancri (circled)

A light curve for Kappa Cancri, plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cancer
Right ascension 09h 07m 44.80955s[2]
Declination +10° 40′ 05.5196″[2]
Apparent magnitude (V) +5.233[3]
Characteristics
Spectral type B8 IIIp[4]
B−V color index −0.113[3]
Variable type α2 CVn[5]
Astrometry
Proper motion (μ) RA: −18.31[2] mas/yr
Dec.: −12.105[2] mas/yr
Parallax (π)5.3209 ± 0.1298 mas[2]
Distance610 ± 10 ly
(188 ± 5 pc)
Absolute magnitude (MV)−0.82[6]
Orbit[7]
Period (P)6.3933 d
Eccentricity (e)0.13
Periastron epoch (T)2440001.95 JD
Argument of periastron (ω)
(secondary)		157°
Semi-amplitude (K1)
(primary)		67.4 km/s
Details[8]
κ Cnc A
Mass4.5 M☉
Radius5.0 R☉
Luminosity322[6] L☉
Surface gravity (log g)3.7±0.1[3] cgs
Temperature12,800±200[3] K
Metallicity [Fe/H]+0.51[6] dex
Rotational velocity (v sin i)6±2[3] km/s
κ Cnc B
Mass2.1 M☉
Radius2.4 R☉
Surface gravity (log g)4.0 cgs
Temperature8,500 K
Rotational velocity (v sin i)40 km/s
Other designations
κ Cnc, 76 Cancri, BD+11°1984, FK5 1238, HD 78316, HIP 44798, HR 3623, SAO 98378[9]
Database references
SIMBADdata

Kappa Cancri, Latinized from κ Cancri, is a blue-white hued binary star system in the zodiac constellation of Cancer. It is faintly visible to the naked eye with an apparent visual magnitude of +5.23.[3] The magnitude difference between the two stars is about 2.6.[10] Based upon an annual parallax shift of 5.3209 mas as seen from the Earth,[2] the system is located roughly 610 light-years from the Sun.

This is a single-lined spectroscopic binary[3] star system with an orbital period of 6.39 days and an eccentricity of 0.13.[7] The primary, component A, has a stellar classification of B8 IIIp,[4] suggesting it is a B-type giant star. It a mercury-manganese star, a type of chemically peculiar star showing large overabundances of those two elements in the outer atmosphere.[3] It is classified as an Alpha2 Canum Venaticorum type variable star and its brightness varies from magnitude +5.22 to +5.27 with a period of five days.[5]

The primary component has 4.5 times the mass of the Sun, five times the Sun's radius, and an effective temperature of 13,200 K. The secondary, component B, is a smaller star with 2.1 times the mass and 2.4 times the radius of the Sun, having an effective temperature of 8,500 K.[8]

References

  1. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 5 December 2022.
  2. ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  3. ^ a b c d e f g h Maza, Natalia L.; et al. (December 2014), "A non-LTE spectral analysis of the 3He and 4He isotopes in the HgMn star κ Cancri", Astronomy & Astrophysics, 572: 7, arXiv:1412.2052, Bibcode:2014A&A...572A.112M, doi:10.1051/0004-6361/201425037, S2CID 119116996, A112.
  4. ^ a b Levato, H. (1975), "Rotational velocities and spectral types for a sample of binary systems", Astronomy and Astrophysics, 19: 91, Bibcode:1975A&AS...19...91L.
  5. ^ a b Samus', N. N.; et al. (January 2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  6. ^ a b c 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, S2CID 119257644.
  7. ^ a b Pourbaix, D.; et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy & Astrophysics, 424 (2): 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
  8. ^ a b Ryabchikova, T. (April 1998), "Abundance analysis of SB2 binary stars with HgMn primaries", Contributions of the Astronomical Observatory Skalnate Pleso, 27 (3): 319–323, arXiv:astro-ph/9805063, Bibcode:1998CoSka..27..319R.
  9. ^ "kap Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-19.
  10. ^ Ryabchikova, T.; et al. (April 1998), "Discovery of the secondary star of the HgMn binary kappa CANCRI", Contributions of the Astronomical Observatory Skalnate Pleso, 27 (3): 258–260, arXiv:astro-ph/9805143, Bibcode:1998CoSka..27..258R.
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