Chi Capricorni

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Chi Capricorni
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Capricornus
Right ascension 21h 08m 33.62529s[1]
Declination −21° 11′ 37.2177″[1]
Apparent magnitude (V) +5.28[2]
Spectral type A0 V[3]
B−V color index +0.01[2]
Proper motion (μ) RA: +19.83[1] mas/yr
Dec.: −60.15[1] mas/yr
Parallax (π) 18.14 ± 0.31[1] mas
Distance 180 ± 3 ly
(55.1 ± 0.9 pc)
Absolute magnitude (MV) +1.59[4]
Mass 2.78 M
Luminosity 21[6] L
Surface gravity (log g) 4.33±0.14 cgs
Temperature 10,878±370 K
Metallicity [Fe/H] −0.41±0.06[7] dex
Rotational velocity (v sin i) 212[3] km/s
Age 251 Myr
Other designations
χ Cap, 25 Cap, BD−21° 5933, FK5 3690, HD 201184, HIP 104365, HR 8087, SAO 190050[8]
Database references

Chi Capricorni, Latinized from χ Capricorni, is a star in the southern constellation of Capricornus. Based upon an annual parallax shift of 18.14 mas as seen from the Earth,[1] the star is located about 180 light years from the Sun. It is visible to the naked eye with an apparent visual magnitude of +5.28.[2]

This is an A-type main sequence star with a stellar classification of A0 V.[3] It is a candidate Lambda Boötis star, showing a chemically peculiar spectrum with a low abundance of most elements heavier than oxygen.[7] The star is around 251[5] million years old and is spinning rapidly with a projected rotational velocity of 212[3] km/s. It has 2.78[5] times the mass of the Sun and is radiating 21[6] times the solar luminosity from its photosphere at an effective temperature of 10,878 K.[5]

At an angular separation of 1,199[9] arcseconds lies a faint proper motion companion designated HIP 99550. At the estimated distance of Chi Capricorni, this is equal to a projected separation of 28,300 AU.[9] It has a visual magnitude of 10.94[10] and a classification of M0 Vk,[11] indicating this is a red dwarf star.[9]

Chinese Name[edit]

In Chinese, 十二國 (Shíer Guó), meaning Twelve States, refers to an asterism which is represent twelve ancient states in the Spring and Autumn period and the Warring States period, consisting of χ Capricorni, φ Capricorni, ι Capricorni, 38 Capricorni, 35 Capricorni, 36 Capricorni, θ Capricorni, 30 Capricorni, 33 Capricorni, ζ Capricorni, 19 Capricorni, 26 Capricorni, 27 Capricorni, 20 Capricorni, η Capricorni and 21 Capricorni.[12] Consequently, χ Capricorni itself is represent the state Qi (),[13] together with 112 Herculis in Left Wall of Heavenly Market Enclosure (asterism).[14]

R.H.Allen had opinion that χ Capricorni, together with φ Capricorni, were represent the state Wei (魏).[15]


  1. ^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752Freely accessible, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c Evans, D. S. (1966), "Fundamental data for Southern stars (6th list).", Royal Observatory Bulletin, 110, Bibcode:1966RGOB..110..185E. 
  3. ^ a b c d Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, Bibcode:2007A&A...463..671R, arXiv:astro-ph/0610785Freely accessible, doi:10.1051/0004-6361:20065224. 
  4. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, Bibcode:2012AstL...38..331A, arXiv:1108.4971Freely accessible, doi:10.1134/S1063773712050015. 
  5. ^ a b c d 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, Bibcode:2015ApJ...804..146D, arXiv:1501.03154Freely accessible, doi:10.1088/0004-637X/804/2/146. 
  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, Bibcode:2012MNRAS.427..343M, arXiv:1208.2037Freely accessible, doi:10.1111/j.1365-2966.2012.21873.x. 
  7. ^ a b Andrievsky, S. M.; et al. (December 2002), "The elemental abundance pattern of twenty lambda Bootis candidate stars", Astronomy and Astrophysics, 396: 641−648, Bibcode:2002A&A...396..641A, doi:10.1051/0004-6361:20021423. 
  8. ^ "chi Cap -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-05-09. 
  9. ^ a b c Dhital, Saurav; et al. (June 2010), "Sloan Low-mass Wide Pairs of Kinematically Equivalent Stars (SLoWPoKES): A Catalog of Very Wide, Low-mass Pairs", The Astronomical Journal, 139 (6): 2566–2586, Bibcode:2010AJ....139.2566D, arXiv:1004.2755Freely accessible, doi:10.1088/0004-6256/139/6/2566. 
  10. ^ Høg, E.; et al. (March 2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy and Astrophysics, 355: L27−L30, Bibcode:2000A&A...355L..27H. 
  11. ^ Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal, 132 (1): 161–170, Bibcode:2006AJ....132..161G, arXiv:astro-ph/0603770Freely accessible, doi:10.1086/504637. 
  12. ^ (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.
  13. ^ (in Chinese)zh:北方中西星名對照表
  14. ^ (in Chinese)zh:北天中西星名對照表
  15. ^ Allen, Richard Hinckley (1963), "Capricornus", Star Names, Their Lore and Meaning, Dover, retrieved 2017-05-09.