Gamma Boötis

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γ Boötis
Boötes constellation map.png
γ Boötis (upper center)
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension  14h 32m 04.67180s[1]
Declination +38° 18′ 29.7043″[1]
Apparent magnitude (V) +3.03[2]
Spectral type A7 III[3]
U−B color index +0.12[2]
B−V color index +0.19[2]
R−I color index +0.08
Variable type Delta Scuti variable[3]
Radial velocity (Rv)−35.5[4] km/s
Proper motion (μ) RA: −115.71[1] mas/yr
Dec.: +151.16[1] mas/yr
Parallax (π)37.58 ± 0.14[1] mas
Distance86.8 ± 0.3 ly
(26.61 ± 0.10 pc)
Absolute magnitude (MV)+0.91[5]
Luminosity34[3] L
Temperature7,800[3] K
Metallicity [Fe/H]−0.20 dex
Rotational velocity (v sin i)140[3] km/s
Other designations
Seginus, Haris, Ceginus, Segin, 27 Boötis, BD+38°2565, FK5 535, HD 127762, HIP 71075, HR 5435, SAO 64203, WDS J14321+3818A.[6]
Database references

Gamma Boötis (γ Boötis, abbreviated Gamma Boo, γ Boo) is a binary star[7] in the constellation of Boötes. It is a Delta Scuti type variable star with a period of 1.13 hours.[3] Its brightness varies from magnitude +3.02 to +3.07. Based on parallax measurements obtained during the Hipparcos mission, it is approximately 85 light-years distant from the Sun.

Gamma Boötis forms the primary or 'A' component of a double star system designated WDS J14321+3818 ('B' is the star UCAC2 45176266[8]). Gamma Boötis' two components are themselves designated WDS J14321+3818Aa (officially named Seginus /sɪˈnəs/, the traditional name of the Gamma Bootis system)[9] and Ab.


γ Boötis (Latinised to Gamma Boötis) is the binary's Bayer designation. WDS J14321+3818 is the wider system's designation in the Washington Double Star Catalog. The designations of the two constituents as WDS J14321+3818A and B, and those of A's components - WDS J14321+3818Aa and Ab - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[10]

Gamma Boötis bore the traditional name Seginus (alternatively Segin, Ceginus) of uncertain origin but possibly resulting from Latinisation of an Arabic form of the Greek name of the constellation of Boötes - Theguius.[citation needed] In 2016, the IAU organized a Working Group on Star Names (WGSN)[11] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[12] It approved the name Seginus for WDS J14321+3818Aa on 21 August 2016 and it is now so included in the List of IAU-approved Star Names.[9]

Gamma Boötis was listed as Haris in Bečvář, apparently derived from the Arabic name of the constellation of Boötes, Al-Haris Al-Sama meaning "the guard of the north".[13]

In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Menkib al Aoua al Aisr (منكب العواء الأيسر - mankibu lʿawwaaʾi lʾaysar), which was translated into Latin as Humerus Sinister Latratoris, meaning 'the left shoulder of barker'.[14]

In Chinese astronomy, Gamma Boötis is called 招搖, Pinyin: Zhāoyáo, meaning Twinkling Indicator, because this star is marking itself and standing alone in Twinkling Indicator asterism, Root mansion (see : Chinese constellation).[15] 招搖 (Zhāoyáo), westernized into Chaou Yaou, but the name Chaou Yaou was designated for Beta Boötis (Nekkar) by R.H. Allen and the meaning is "to beckon, excite, or move." [16]


USS Seginus (AK-133) was a United States Navy Crater class cargo ship named after the star.


Gamma Boötis presents as an A-type giant star belonging to spectral class A7III.


  1. ^ a b c d e 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.
  2. ^ a b c Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", SIMBAD, Bibcode:1986EgUBV........0M.
  3. ^ a b c d e f Balona, L. A.; Dziembowski, W. A. (October 1999), "Excitation and visibility of high-degree modes in stars", Monthly Notices of the Royal Astronomical Society, 309 (1): 221–232, Bibcode:1999MNRAS.309..221B, doi:10.1046/j.1365-8711.1999.02821.x
  4. ^ Wilson, R. E. (1953), General Catalogue of Stellar Radial Velocities, Carnegie Institute of Washington D.C., Bibcode:1953GCRV..C......0W.
  5. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  6. ^ "* gam Boo -- Variable Star of delta Sct type". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-12-18.
  7. ^ "Washington Double Star Catalog". United States Naval Observatory. Retrieved 2018-07-24.
  8. ^ "UCAC2 45176266 -- Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2018-07-24.
  9. ^ a b "Naming Stars". Retrieved 18 June 2018.
  10. ^ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
  11. ^ "IAU working group on star names (WGSN)". Retrieved 22 May 2016.
  12. ^ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  13. ^ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
  14. ^ Knobel, E. B. (June 1895). "Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket". Monthly Notices of the Royal Astronomical Society. 55: 429. Bibcode:1895MNRAS..55..429K. doi:10.1093/mnras/55.8.429.
  15. ^ ‹See Tfd›(in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 29 日
  16. ^ Richard Hinckley Allen: Star Names — Their Lore and Meaning: Boötes

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