Lambda Cancri

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Lambda Cancri
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cancer
Right ascension 08h 20m 32.13630s[1]
Declination +24° 01′ 20.3198″[1]
Apparent magnitude (V) +5.93[2]
Spectral type B9.5 V[3][2]
Radial velocity (Rv) +23.0±4.3[4] km/s
Proper motion (μ) RA: −20.29[1] mas/yr
Dec.: −18.81[1] mas/yr
Parallax (π) 7.13 ± 0.38[1] mas
Distance 460 ± 20 ly
(140 ± 7 pc)
Absolute magnitude (MV) +0.19[5]
λ Cnc A
Mass 2.1+0.39
Luminosity 78[6] L
Surface gravity (log g) 4.0±0.25 cgs
Temperature 9,500±1,000 K
Rotational velocity (v sin i) 188[7] km/s
Age 105+287
λ Cnc B
Mass 0.8 M
Temperature 4,562±154 K
Rotational velocity (v sin i) 10 km/s
Other designations
λ Cnc, 19 Cancri, BD+24° 1909, HD 70011, HIP 40881, HR 3268, SAO 80113[8]
Database references

Lambda Cancri, Latinized from λ Cancri, is a blue-white hued binary star[2] system in the zodiac constellation of Cancer. It is faintly visible to the naked eye with an apparent visual magnitude of +5.93.[2] Based upon an annual parallax shift of 7.13 mas as seen from Earth,[1] this star is located around 460 light years from the Sun.

The primary, component A, is a B-type main sequence star with a stellar classification of B9.5 V.[3] It has 2.1[2] times the mass of the Sun and radiates 78[6] times the Sun's luminosity from its photosphere at an effective temperature of roughly 9,500 K.[2] A close companion, component B, has 80% of the mass of the Sun.[2]

In Chinese, (Guàn), meaning Beacon Fire, refers to an asterism consisting of λ Cancri, ψ Cancri, φ1 Cancri and 15 Cancri.[9] Consequently, λ Cancri itself is known as 爟二 (Guàn èr, English: the Second Star of Beacon Fire.).[10] From this Chinese name, the name Kwan Wei meaning "the bright fire" was given.[11]


  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:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d e f g h Gullikson, Kevin; et al. (August 2016), "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars", The Astronomical Journal, 152 (2): 13, arXiv:1604.06456Freely accessible, Bibcode:2016AJ....152...40G, doi:10.3847/0004-6256/152/2/40, 40. 
  3. ^ a b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819. 
  4. ^ 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:1208.3048Freely accessible, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61. 
  5. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971Freely accessible, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. 
  6. ^ 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:1208.2037Freely accessible, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x. 
  7. ^ Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785Freely accessible, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224. 
  8. ^ "lam Cnc -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-06-18. 
  9. ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  10. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 27 日
  11. ^ Allen, Richard Hinckley (1963), Star Names — Their Lore and Meaning: Cancer (Dover ed.), retrieved 2017-06-19.