The double nature of this system was discovered by American astronomer S. W. Burnham in 1878, and has the discovery code BU 616.[15] The system is resolved into a pair separated by 33.4 arcseconds with a magnitude difference of 9.27. The brighter primary is itself a close pair separated by 0.069″,[16] as discovered by B. L. Morgan and associates in 1975.[15] The primary or 'A' component of this double star system is designated WDS J14321+3818 ('B' is the star UCAC2 45176266[17]) in the Washington Double Star Catalog. Parallax measurements for component B give a distance of approximately 1,996 light-years.[18] Gamma Boötis' two components are themselves designated WDS J14321+3818Aa (Seginus)[14] and Ab.
The stellar classification of Gamma Boötis is A7IV+(n),[2] matching an A-type star with somewhat "nebulous" lines due to rapid rotation. It was found to be a short-period variable star in 1914 by German astronomers P. Guthnick and R. Prager. Non-radial pulsations were detected in 1992 by Edward J. Kennelly and colleagues.[10] It is a Delta Scuti-typevariable star with a period of 6.96753 h that varies from magnitude +3.02 down to +3.07.[3] This dominant mode is 21.28 cycles per day with an amplitude of 0.05 in magnitude.[10] Additional pulsations occur at 18.09, 12.02, 11.70 and 5.06 cycles per day.[4]
The system displays a statistically significant infrared excess due to a circumstellar disk. A model fit to the data indicates this material has a mean temperature of 85 K and is orbiting at a distance of 99±10 AU.[9]
Gamma Boötis bore the traditional name Ceginus (later Seginus), from cheguiusortheguius, apparently Latin mistranscriptions of an Arabic rendering of Greek Boötes.[22] Two possibilities have been suggested: from Arabic بوطس bwṭs, in one of the manuscripts of the Almagest, with undotted ب b mistaken for an undotted ث th, و w taken as w and spelled 'gu', and ط ṭ completely misread,[23] or from Arabic بؤوتس bwʾwts, with undotted ب b mistaken for an undotted ث th, ؤ w-hamza mistaken for غ ġ, و w read as u, and undotted ن n misread as an undotted ى y and transcribed i—that is, as th-g-u-i-s with unwritten vowels (and the Latin grammatical ending -us) filled in for theguius.[24]
In 2016, the IAU organized a Working Group on Star Names (WGSN)[25] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[26] 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.[14]
Gamma Boötis was listed as HarisinBečvář, apparently derived from the Arabic name of the constellation of Boötes, Al-Haris Al-Sama meaning "the guard of the north".[22]
In the catalogue of stars in the CalendariumofAl Achsasi al Mouakket, this star was designated Menkib al Aoua al Aisr (منكب العواء الأيسر – mankibu lʿawwaaʾi lʾaysar), which was translated into LatinasHumerus Sinister Latratoris, meaning 'the left shoulder of barker'.[27]
InChinese astronomy, Gamma Boötis is called 招搖, Pinyin: Zhāoyáo, meaning Twinkling Indicator, because this star is marking itself and standing alone in Twinkling Indicatorasterism, Root mansion (see: Chinese constellation).[28] 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."[13]
^ abcdGray, R. O.; et al. (April 2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal, 121 (4): 2148–2158, Bibcode:2001AJ....121.2148G, doi:10.1086/319956.
^ abcYelverton, Ben; et al. (September 2019), "A statistically significant lack of debris discs in medium separation binary systems", Monthly Notices of the Royal Astronomical Society, 488 (3): 3588–3606, arXiv:1907.04800, Bibcode:2019MNRAS.488.3588Y, doi:10.1093/mnras/stz1927.
^Morgan, B. L.; et al. (June 1978), "Observations of binary stars by speckle interferometry - I.", Monthly Notices of the Royal Astronomical Society, 183 (4): 701–710, Bibcode:1978MNRAS.183..701M, doi:10.1093/mnras/183.4.701.
^Hessman, F. V.; et al. (2010), On the naming convention used for multiple star systems and extrasolar planets, arXiv:1012.0707, Bibcode:2010arXiv1012.0707H, 1012.0707.
^ abKunitzsch, 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 Pubublishing Company, ISBN978-1-931559-44-7.
^Kunitzsch, Paul (1959), Arabische sternnamen in europa, pp. 152–153.
^Laffitte, Roland (2001), Héritages arabes des noms arabes pour les étoiles, p. 160.
