Beta Serpentis, Latinized from β Serpentis, is a binary star[3] system in the constellation Serpens, in its head (Serpens Caput). It is visible to the naked eye with a combined apparent visual magnitude of +3.65.[2] Based upon an annual parallax shift of 21.03 mas as seen from Earth,[1] it is located around 155 light years from the Sun. The system is a member of the Ursa Major Moving Group.[7]


The visual magnitude +3.68 primary, component A, is either an ordinary A-type main-sequence star or somewhat evolved subgiant with a stellar classification of A2 V[4] or A2 IV,[5] respectively. The star is about 267 million years old with nearly double the mass of the Sun.[8] It is spinning rapidly with a projected rotational velocity of 207 km/s.[4]

The secondary component, visual magnitude 9.7 B, lies at an angular separation of 30.6 arc seconds. It is a main-sequence star with a class of K3 V.[3]

There is a magnitude +10.98 visual companion, designated component C, located 202 arcseconds away.[10]


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 γ Ser (Zheng, Ching).[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]

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 β Serpentis, β Herculis, γ Herculis, κ Herculis, γ Serpentis, δ Serpentis, α Serpentis, ε Serpentis, δ Ophiuchi, ε Ophiuchi and ζ Ophiuchi.[14] Consequently, β Serpentis itself is known as 天市右垣五 (Tiān Shì Yòu Yuán wu, English: the Fifth Star of Right Wall of Heavenly Market Enclosure), represent Zhou (周) (possibly Chow, the dynasty in China),[15][16][17] together with η Capricorni and 21 Capricorni in Twelve States (asterism).[18]


  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 Lutz, T. E.; Lutz, J. H. (June 1977), "Spectral classification and UBV photometry of bright visual double stars", Astronomical Journal, 82: 431–434, Bibcode:1977AJ.....82..431L, doi:10.1086/112066. 
  3. ^ a b c d Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869, arXiv:0806.2878Freely accessible, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x. 
  4. ^ a b c d e Jones, Jeremy; et al. (November 2015), "The Ages of A-Stars. I. Interferometric Observations and Age Estimates for Stars in the Ursa Major Moving Group", The Astrophysical Journal, 813 (1): 18, arXiv:1508.05643Freely accessible, Bibcode:2015ApJ...813...58J, doi:10.1088/0004-637X/813/1/58, 58. 
  5. ^ a b Gray, R. O.; Garrison, R. F. (December 1987), "The Early A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation", Astrophysical Journal Supplement, 65: 581, Bibcode:1987ApJS...65..581G, doi:10.1086/191237. 
  6. ^ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053Freely accessible, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065. 
  7. ^ a b King, Jeremy R.; et al. (April 2003), "Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group", The Astronomical Journal, 125 (4): 1980–2017, Bibcode:2003AJ....125.1980K, doi:10.1086/368241. 
  8. ^ a b c d e 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, arXiv:1501.03154Freely accessible, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146. 
  9. ^ "bet Ser". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-22. 
  10. ^ Mason, B. D.; et al. (2014), The Washington Visual Double Star Catalog, Bibcode:2001AJ....122.3466M, doi:10.1086/323920 
  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) [1899], "Hercules", Star Names: Their Lore and Meaning (Dover ed.), New York, NY: Dover Publications Inc, p. 243, ISBN 0-486-21079-0, retrieved 2017-09-22. 
  13. ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), California Institute of Technology: Jet Propulsion Laboratory. 
  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. ^ Allen, R. H. (1963) [1899], "Serpens", Star Names: Their Lore and Meaning (Dover ed.), New York, NY: Dover Publications Inc, p. 376, ISBN 0-486-21079-0, retrieved 2017-09-22. 
  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 2010-08-10 at the Wayback Machine., Hong Kong Space Museum. Accessed on line November 23, 2010.
  18. ^ Allen, R. H. (1963) [1899], "Capricornus", Star Names: Their Lore and Meaning (Dover ed.), New York, NY: Dover Publications Inc, p. 142, ISBN 0-486-21079-0, retrieved 2017-09-22.