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Gamma Serpentis (γ Serpentis, γ Ser) is a star in the equatorial constellation Serpens, in the part of the constellation that represents the serpent's head (Serpens Caput). It has an apparent visual magnitude +3.85,[2] which means it is visible to the naked eye. Based upon parallax measurements by the Hipparcos spacecraft, this star is approximately 36.7 light years from Earth.[1]

Gamma Serpentis
Observation data
Epoch J2000      Equinox J2000
Constellation Serpens
Right ascension  15h 56m 27.18269s[1]
Declination +15° 39′ 41.8206″[1]
Apparent magnitude (V) 3.85[2]
Spectral type F6 V[2]
U−B color index -0.03[3]
B−V color index +0.48[2]
Variable type Suspected[4]
Radial velocity (Rv)6.78 ± 0.09[5] km/s
Proper motion (μ) RA: 310.93 ± 0.20[1] mas/yr
Dec.: -1282.19 ± 0.18[1] mas/yr
Parallax (π)88.86 ± 0.18[1] mas
Distance36.70 ± 0.07 ly
(11.25 ± 0.02 pc)
Absolute magnitude (MV)3.60[6]
Mass1.30 ± 0.15[7] M
Radius1.55 ± 0.05[7] R
Luminosity3.02 ± 0.09[7] L
Surface gravity (log g)4.23[2] cgs
Temperature6,350 ± 310[2] K
Metallicity [Fe/H]−0.19[7] dex
Rotational velocity (v sin i)10.2[7] km/s
Age3.49[8] Gyr
Other designations
Ainalhai, 41 Serpentis, BD+16° 2849, FK5 591, GCTP 3604.00, HD 142860, HIP 78072, HR 5933, LHS 408, SAO 101826.[9]
Database references


Gamma Serpentis is an ordinary F-type main sequence star with a stellar classification of F6 V.[2] It is larger and more massive than the Sun, with three times the solar luminosity.[7] Based upon its mass, it may have a convection zone in its core region.[4] The projected rotational velocity along the equator is 10.2[7] km/s. It is younger than the Sun with an estimated age of 3.5 billion years.[8] The effective temperature of the star's outer atmosphere is 6,350 K,[2] giving it the yellow-white-hued glow of an F-type star.[10]

Occasionally Gamma Serpentis is listed as having two 10th magnitude companions, but it appears that these stars are just optical neighbours.


It was a member of indigenous Arabic asterism al-Nasaq al-Sha'āmī, "the Northern Line" of al-Nasaqān "the Two Lines",[11] along with β Her (Kornephoros), γ Her (Hejian, Ho Keen) and β Ser (Chow).[12]

According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, al-Nasaq al-Sha'āmī or Nasak Shamiya were the title for three stars:β Ser as Nasak Shamiya I, γ Ser as Nasak Shamiya II, γ Her as Nasak Shamiya III (exclude β Her).[13] The star was later given the proper name Ainalhai, from the Arabic عين الحية ‘Ayn al-Ḥayyah "the Serpent's Eye".

In Chinese, 天市右垣 (Tiān Shì Yòu Yuán), meaning Right Wall of Heavenly Market Enclosure, refers to an asterism which is represent eleven old states in China which is marking the right borderline of the enclosure, consisting of γ Serpentis, β Herculis, γ Herculis, κ Herculis, β Serpentis, δ Serpentis, α Serpentis, ε Serpentis, δ Ophiuchi, ε Ophiuchi and ζ Ophiuchi.[14] Consequently, the Chinese name for γ Serpentis itself is 天市右垣四 (Tiān Shì Yòu Yuán sì, English: the Fourth Star of Right Wall of Heavenly Market Enclosure), represent the state Zheng (鄭) (or Ching),[15][16][17] together with 20 Capricorni (according to Ian Ridpath version[18]) in Twelve States (asterism).


  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. Vizier catalog entry
  2. ^ a b c d e f g h Malagnini, M. L.; Morossi, C. (November 1990), "Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars", Astronomy and Astrophysics Supplement Series, 85 (3): 1015–1019, Bibcode:1990A&AS...85.1015M
  3. ^ Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode:1986EgUBV........0M.
  4. ^ a b Bi, S.-L.; Basu, Sarbani; Li, L.-H. (February 2008), "Seismological Analysis of the Stars γ Serpentis and ι Leonis: Stellar Parameters and Evolution", The Astrophysical Journal, 673 (2): 1093–1105, Bibcode:2008ApJ...673.1093B, doi:10.1086/521575.
  5. ^ Nidever, David L.; et al. (August 2002), "Radial Velocities for 889 Late-Type Stars", The Astrophysical Journal Supplement Series, 141 (2): 503–522, arXiv:astro-ph/0112477, Bibcode:2002ApJS..141..503N, doi:10.1086/340570.
  6. ^ Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191.
  7. ^ a b c d e f g Bruntt, H.; et al. (July 2010), "Accurate fundamental parameters for 23 bright solar-type stars", Monthly Notices of the Royal Astronomical Society, 405 (3): 1907–1923, arXiv:1002.4268, Bibcode:2010MNRAS.405.1907B, doi:10.1111/j.1365-2966.2010.16575.x
  8. ^ a b Vican, Laura (June 2012), "Age Determination for 346 Nearby Stars in the Herschel DEBRIS Survey", The Astronomical Journal, 143 (6): 135, arXiv:1203.1966, Bibcode:2012AJ....143..135V, doi:10.1088/0004-6256/143/6/135.
  9. ^ "* gam Ser". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2007-01-23.
  10. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-10, retrieved 2012-01-16.
  11. ^ Kunitzsch, P., Smart, T. (2006), A Dictionary of Modern Star names: A Short Guide to 254 Star names and Their Derivations (Second Revised ed.), Cambridge, MA: Sky Publishing, p. 31, ISBN 1-931559-44-9
  12. ^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc, p. 243, ISBN 0-486-21079-0, retrieved 2010-12-12
  13. ^ Jack W. Rhoads - Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology; November 15, 1971
  14. ^ (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.
  15. ^ Star Names - R.H.Allen p.376
  16. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 24 日
  17. ^ (in Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Archived August 10, 2010, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  18. ^ Ian Ridpath's Startales - Capricornus the Sea Goat

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