Xi Cancri
Location of Nahn (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cancer
Right ascension 09h 09m 21.53325s[1]
Declination +22° 02′ 43.6053″[1]
Apparent magnitude (V) +5.15[2] (5.70 + 6.20)[3]
Characteristics
Spectral type G9 III Fe-1 CH-0.5[4]
U−B color index +0.75[2]
B−V color index +0.96[2]
Astrometry
Radial velocity (Rv)+7.7±0.3[5] km/s
Proper motion (μ) RA: −1.00[1] mas/yr
Dec.: −0.52[1] mas/yr
Parallax (π)8.74 ± 0.49 mas[1]
Distance370 ± 20 ly
(114 ± 6 pc)
Absolute magnitude (MV)−0.12[4]
Orbit[6][7]
Period (P)1,700.76 d
Semi-major axis (a)0.0105±0.0017[3]″
Eccentricity (e)0.06
Periastron epoch (T)2,428,876.86 ± 10.0 JD
Argument of periastron (ω)
(secondary)		301.1°
Semi-amplitude (K1)
(primary)		4.4 km/s
Details
Luminosity118[8] L☉
Temperature5,101[8] K
Other designations
Nahn, ξ Cnc, 77 Cancri, BD+22° 2061, FK5 1239, HD 78515, HIP 44946, HR 3627, SAO 80666[9]
Database references
SIMBADdata

Xi Cancri (ξ Cancri, abbreviated Xi Cnc, ξ Cnc) is a spectroscopic binary star system in the zodiac constellation of Cancer. It is visible to the naked eye with an apparent visual magnitude of +5.15.[2] Based upon parallax measurements obtained during the Hipparcos mission,[1] it is roughly 370 light-years distant from the Sun.

The two components are designated Xi Cancri A (formally named Nahn /ˈnɑːn/)[10] and B.

Nomenclature

ξ Cancri (Latinised to Xi Cancri) is the system's Bayer designation. The designations of the two components as Xi Cancri A and B derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[11]

Xi Cancri together with Lambda Leonis (Alterf) were the Persian Nahn, "the Nose", and the Coptic Piautos, "the Eye", both lunar asterisms.[12] Nahn was also the name given to Xi Cancri in a 1971 NASA technical memorandum.[13] In 2016, the IAU organized a Working Group on Star Names (WGSN)[14] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[15] It approved the name Nahn for the component Xi Cancri A on 1 June 2018 and it is now so included in the List of IAU-approved Star Names.[10]

Properties

At its present distance, the visual magnitude is diminished by an extinction factor of 0.135 due to interstellar dust.[3]

Xi Cancri is a single-lined spectroscopic binary star system with an orbital period of 4.66 years, an eccentricity of 0.06, and a semimajor axis of 0.01 arcsecond. The primary, Xi Cancri A, is a yellow G-type giant with an apparent magnitude of +5.70. Its companion, Xi Cancri B, is of magnitude 6.20.[3]

References

  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, S2CID 18759600.
  2. ^ a b c d Sturch, C. R.; Helfer, H. L. (November 1972), "UBVRI photometry of north galactic pole K giants. II", Astronomical Journal, 77: 726, Bibcode:1972AJ.....77..726S, doi:10.1086/111344.
  3. ^ a b c d Malkov, O. Yu.; et al. (2012), "Dynamical masses of a selected sample of orbital binaries", Astronomy & Astrophysics, 546: A69, Bibcode:2012A&A...546A..69M, doi:10.1051/0004-6361/201219774.
  4. ^ a b 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.
  5. ^ 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, S2CID 59451347, A61.
  6. ^ 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.
  7. ^ Jackson, E. S.; et al. (May 1957), "The Orbits of the Spectroscopic Binaries Omicron Tauri, Xi Cancri, and Mu Ursae Majories", Astrophysical Journal, 125: 712, Bibcode:1957ApJ...125..712J, doi:10.1086/146345.
  8. ^ a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
  9. ^ "ksi Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-15.
  10. ^ a b "Naming Stars". IAU.org. Retrieved 18 June 2018.
  11. ^ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
  12. ^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc., p. 114, ISBN 0-486-21079-0, retrieved 2010-12-12.
  13. ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), Jet Propulsion Laboratory, California Institute of Technology.
  14. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  15. ^ "WG Triennial Report (2015–2018) – Star Names" (PDF). p. 5. Retrieved 2018-07-14.
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