Alpha Serpentis

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Double star in the constellation Serpens

title: "Alpha Serpentis" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["k-type-giants", "cn-stars", "serpens", "bayer-objects", "durchmusterung-objects", "flamsteed-objects", "henry-draper-catalogue-objects", "hipparcos-objects", "bright-star-catalogue-objects", "stars-with-proper-names", "horizontal-branch-stars", "population-i-stars", "lucidae"] description: "Double star in the constellation Serpens" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Alpha_Serpentis" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Double star in the constellation Serpens ::

| name=α Serpentis | image = | image=Serpens Caput IAU.svg | float=center | width=250 | position=right | mark=Red circle.svg | mark_width=10 | mark_link=π Sco | x%=47.2 | y%=52.6 | caption=Location of α Serpentis (circled) | epoch = J2000 | ra = | dec = | appmag_v = 2.623 | constell = Serpens | class = K2 IIIb CN1 | b-v = +1.167 | u-b = +1.248 | variable = |type=Horizontal branch}} | radial_v = +2.63 | prop_mo_ra = +133.84 | prop_mo_dec = +44.81 | parallax = 44.10 | p_error = 0.19 | parallax_footnote = | absmag_v = | mass = | radius = 12.19 | luminosity = | temperature = | gravity = 2.4 | metal_fe = 0.189 | rotational_velocity = 4.3 | age_gyr = | names = |Simbad=alf+Ser

Alpha Serpentis or α Serpentis, formally named Unukalhai (),{{cite book |last1=Kunitzsch |first1=Paul |last2=Smart |first2=Tim |date = 2006 |edition = 2nd rev. |title = A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations |publisher = Sky Pub |location = Cambridge, Massachusetts |isbn = 978-1-931559-44-7

Properties

Alpha Serpentis is a giant star with a stellar classification of K2IIIbCN1, having consumed the hydrogen at its core and evolved away from the main sequence. It has 1.6 times the mass and 13.5 times the radius of the Sun. It is most likely a horizontal branch or red clump star, fusing helium into carbon and heavier elements within its core. The effective temperature of the outer envelope is 4,687 K, giving it an orange hue that is characteristic of a K-type star. It has been classified as a strong CN star, showing a higher than expected strength in the cyanogen bands.

This star is radiating about 30 times the luminosity of the Sun, while a further 32 times the Sun's luminosity is being emitted in the infrared, for 70-fold total.

Nomenclature

α Serpentis (Latinised to Alpha Serpentis) is the system's Bayer designation.

It bore the traditional names Unukalhai (alternatively spelt Unuk al Hay or Unuk Elhaija) from the Arabic عنق الحيّة ʽunuq al-ḥayyah "the serpent's neck", and Cor Serpentis from the Latin "the Heart of the Serpent". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN){{citation | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN) | publisher=International Astronomical Union | access-date=22 May 2016 | postscript=. }} to catalogue and standardize proper names for stars. The WGSN approved the name Unukalhai for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.

Alpha Serpentis is a member of the indigenous Arabic asterism al-Nasaq al-Yamānī "the Southern Line" of al-Nasaqān "the Two Lines",

In Chinese, 天市右垣 (Tiān Shì Yòu Yuán), meaning Right Wall of Heavenly Market Enclosure, refers to an asterism which represents eleven old states in China and which is marking the right borderline of the enclosure, consisting of Alpha Serpentis, Beta Herculis, Gamma Herculis, Kappa Herculis, Gamma Serpentis, Beta Serpentis, Delta Serpentis, Epsilon Serpentis, Delta Ophiuchi, Epsilon Ophiuchi and Zeta Ophiuchi. Consequently, the Chinese name for Alpha Serpentis itself is 天市右垣七 (Tiān Shì Yòu Yuán qī, ), and represents the state Shu (蜀) (or Shuh) (together with Lambda Serpentis in R.H.Allen's works).

References

References

  1. "IAU Catalog of Star Names".
  2. along with [[Delta Serpentis]], [[Epsilon Serpentis]], [[Delta Ophiuchi]], [[Epsilon Ophiuchi]], [[Zeta Ophiuchi]] and [[Gamma Ophiuchi]]. According to a 1971 [[NASA]] catalogue, ''al-Nasaq al-Yamānī'' or ''Nasak Yamani'' was the name for two stars: [[Delta Serpentis]] as ''Nasak Yamani I'' and [[Epsilon Serpentis]] as ''Nasak Yamani II''.[https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720005197_1972005197.pdf 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]
  3. {{in lang. zh ''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.
  4. {{in lang. zh [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_t_z.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive. link. (2010-08-19 , Hong Kong Space Museum. Accessed on line November 23, 2010.)
  5. {{in lang. zh [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm#HeavenlyMarketEnclosure English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name] {{webarchive. link. (2008-09-24 , Hong Kong Space Museum. Accessed on line November 23, 2010.)
  6. van Leeuwen, F.. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics.
  7. (January 2008). "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity". The Astronomical Journal.
  8. (January 2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics.
  9. (2018). "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer". The Astronomical Journal.
  10. (1966). "A System of photometric standards". Publicaciones Universidad de Chile, Department de Astronomy.
  11. "UNUKALHAI -- Star in double system". [[Centre de Données astronomiques de Strasbourg]].
  12. "UNUKALHAI (Alpha Serpentis)". [[University of Illinois]].
  13. (2006). "A Dictionary of Modern Star names: A Short Guide to 254 Star names and Their Derivations". Sky Publishing.
  14. Allen, R. H.. (1963). "Star Names: Their Lore and Meaning". Dover Publications Inc.
  15. (December 21, 2004). "The Colour of Stars". [[Commonwealth Scientific and Industrial Research Organisation]].
  16. (March 2008). "Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars". The Astronomical Journal.

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k-type-giantscn-starsserpensbayer-objectsdurchmusterung-objectsflamsteed-objectshenry-draper-catalogue-objectshipparcos-objectsbright-star-catalogue-objectsstars-with-proper-nameshorizontal-branch-starspopulation-i-starslucidae