Astronomy:Gamma Cancri

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Short description: Star system in the constellation Cancer
Gamma Cancri
Cancer constellation map.svg
Red circle.svg
Location of γ Cancri (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Cancer
Right ascension  08h 43m 17.14820s[1]
Declination +21° 28′ 06.6008″[1]
Apparent magnitude (V) 4.673[2]
Characteristics
Spectral type A1IV[3]
U−B color index +0.03[4]
B−V color index +0.010[2]
Astrometry
Radial velocity (Rv)28.7[5] km/s
Proper motion (μ) RA: −103.51[1] mas/yr
Dec.: −39.48[1] mas/yr
Parallax (π)18.00 ± 0.21[1] mas
Distance181 ± 2 ly
(55.6 ± 0.6 pc)
Absolute magnitude (MV)+1.1[6]
Details
Mass2.18[7] M☉
Radius2.5[8] R☉
Luminosity36[9] L☉
Surface gravity (log g)4.17[7] cgs
Temperature9,108[9] K
Rotational velocity (v sin i)86±6[10] km/s
Age171[7] Myr
Other designations
Asellus Borealis, γ Cnc, Gamma Cnc, 43 Cnc, BD+21° 1895, FK5 1228, GC 11982, HD 74198, HIP 42806, HR 3449, SAO 80378, CCDM 08433+2128[11]
Database references
SIMBADdata

Gamma Cancri, or γ Cancri, is a star in the northern constellation of Cancer. It is formally named Asellus Borealis /əˈsɛləs bɒriˈælɪs/, the traditional name of the system.[12] Based on parallax measurements, it is located at a distance of approximately 181 light years from the Sun. The star is drifting further away with a radial velocity of 29 km/s.[5] In 1910 this star was reported to be a spectroscopic binary by O. J. Lee,[13] but is now considered a single star.[14][15] Since it is near the ecliptic, it can be occulted by the Moon[16] and, very rarely, by planets.

Nomenclature

γ Cancri (Latinised to Gamma Cancri) is the star's Bayer designation. It bore the traditional name Asellus Borealis (Latin for "northern donkey").[17] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[18] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[19] It approved the name Asellus Borealis for the star on 6 November 2016 and it is now so included in the List of IAU-approved Star Names.[12] Together with Delta Cancri, it formed the Aselli, flanking Praesepe.[20]

In Chinese astronomy, Ghost (Chinese: 鬼宿; pinyin: Guǐ Xiù) refers to an asterism consisting of Theta Cancri, Eta Cancri, Gamma Cancri and Delta Cancri.[21] Gamma Cancri itself is known as the third star of Ghost (Chinese: 鬼宿三; pinyin: Guǐ Xiù sān).[22]

Properties

Gamma Cancri presents as a white A-type subgiant with an apparent magnitude of +4.67.[3] The star is an estimated 171[7] million years old and is spinning with a projected rotational velocity of 86 km/s.[10] It has 2.18[7] times the mass of the Sun and shines with a luminosity approximately 36 times greater at an effective temperature of 9108 K.[9]

It has been included as a member of the Hyades Stream based on its distance, space motion, and likely age.[23]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (2007). "Validation of the New Hipparcos Reduction". Astronomy and Astrophysics 474 (2): 653–64. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. 
  2. ↑ 2.0 2.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  3. ↑ 3.0 3.1 Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement 95: 135. doi:10.1086/192182. Bibcode: 1995ApJS...99..135A. 
  4. ↑ Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M. 
  5. ↑ 5.0 5.1 Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication. Bibcode: 1953GCRV..C......0W. 
  6. ↑ Eggen, O. J.; Iben, Icko, Jr. (1988). "Starbursts, binary stars, and blue stragglers in local superclusters and groups. I - The very young disk and young disk populations". Astronomical Journal 96: 635–669. doi:10.1086/114834. Bibcode: 1988AJ.....96..635E. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 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. doi:10.1088/0004-637X/804/2/146. Bibcode: 2015ApJ...804..146D.  Vizier catalog entry
  8. ↑ Pasinetti Fracassini, L. E. et al. (2001). "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics". Astronomy & Astrophysics 367 (2): 521–24. doi:10.1051/0004-6361:20000451. Bibcode: 2001A&A...367..521P. 
  9. ↑ 9.0 9.1 9.2 McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental Parameters and Infrared Excesses of Hipparcos Stars". Monthly Notices of the Royal Astronomical Society 427 (1): 343–57. doi:10.1111/j.1365-2966.2012.21873.x. Bibcode: 2012MNRAS.427..343M. 
  10. ↑ 10.0 10.1 Royer, F.; Grenier, S.; Baylac, M.-O.; Gómez, A. E.; Zorec, J. (2002). "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i". Astronomy and Astrophysics 393: 897–911. doi:10.1051/0004-6361:20020943. Bibcode: 2002A&A...393..897R. 
  11. ↑ "gam Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=gam+Cnc. 
  12. ↑ 12.0 12.1 "Naming Stars". IAU.org. https://www.iau.org/public/themes/naming_stars/. 
  13. ↑ Lee, Oliver J. (November 1910). "Measures on nineteen new spectroscopic binaries". Astrophysical Journal 32: 300–308. doi:10.1086/141806. Bibcode: 1910ApJ....32..300L. 
  14. ↑ 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. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E. 
  15. ↑ De Rosa, R. J. et al. (July 2011). "The Volume-limited A-Star (VAST) survey - I. Companions and the unexpected X-ray detection of B6-A7 stars". Monthly Notices of the Royal Astronomical Society 415 (1): 854–866. doi:10.1111/j.1365-2966.2011.18765.x. Bibcode: 2011MNRAS.415..854D. 
  16. ↑ Schmidtke, P. C.; Africano, J. L. (January 2011). "KPNO Lunar Occultation Summary. III". The Astronomical Journal 141 (1): 7. doi:10.1088/0004-6256/141/1/10. 10. Bibcode: 2011AJ....141...10S. 
  17. ↑ Dixon-Kennedy, Mike (1998), Encyclopedia of Greco-Roman Mythology, ABC-CLIO, p. 51, ISBN 9781576070949, https://books.google.com/books?id=2U7okUE3PIcC&pg=PA51 
  18. ↑ IAU Working Group on Star Names (WGSN), International Astronomical Union, https://www.iau.org/science/scientific_bodies/working_groups/280/, retrieved 22 May 2016. 
  19. ↑ "WG Triennial Report (2015-2018) - Star Names". p. 5. https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf. 
  20. ↑ Richard H. Allen (28 February 2013). Star Names: Their Lore and Meaning. Courier Corporation. ISBN 978-0-486-13766-7. https://books.google.com/books?id=vWDsybJzz7IC. 
  21. ↑ 陳久金 (2005). Zhōngguó Xīngzuò Shénhuà. 台灣古籍出版有限公司. p. 394. ISBN 978-986-7332-25-7. https://books.google.com/books?id=0Vex0rYzdu8C&pg=394. 
  22. ↑ "Error: no |title= specified when using {{Cite web}}" (in zh). http://www.lcsd.gov.hk/CE/Museum/Space/zh_TW/web/spm/starshine/resources/constemyth/chinengstars/startable1.html. "Asellus Borealis" 
  23. ↑ Eggen, Olin J. (October 1992). "The Hyades Supercluster in FK5". Astronomical Journal 104: 1482. doi:10.1086/116333. Bibcode: 1992AJ....104.1482E. 



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