Editing Theta Scorpii

{{Short description|Star in the constellation Scorpius}}
{{Starbox begin
}}
{{Starbox image
 | image=
   {{Location mark
     | image=Scorpius constellation map.svg
     | float=center | width=250 | position=right
     | mark=Red circle.svg | mark_width=10 | mark_link=θ Sco
     | x%=24.6 | y%=87.6
   }}
 | caption=Location of θ Scorpii (circled)
}}
{{Starbox observe
 | epoch    = J2000
 | ra       = {{RA|17|37|19.12985}}<ref name=aaa474_2_653/>
 | dec      = {{DEC|-42|59|52.1808}}<ref name=aaa474_2_653/>
 | appmag_v = 1.84 {{nowrap|(1.862 + 6.22)<ref name=hog/>}}
 | constell = [[Scorpius]]
}}
{{Starbox character
 | class    = F0Ib-F1III<ref name="ayres2018" /> or F0&nbsp;II<ref name=houk1978/>
 | b-v      = +0.40<ref name=clpl4_99/>
 | u-b      = +0.21<ref name=clpl4_99/>
 | variable =
}}
{{Starbox astrometry
 | radial_v = +1.4<ref name=gcsrv/>
 | prop_mo_ra  = +5.54<ref name=aaa474_2_653/>
 | prop_mo_dec = −3.12<ref name=aaa474_2_653/>
 | parallax = 9.90
 | p_error  = 0.26
 | parallax_footnote = <ref name=Lewis/>
 | absmag_v = −2.71<ref name=Anderson2012/>
}}
{{Starbox detail
 | mass     = {{val|3.10|+0.37|-0.32}}<ref name=Lewis/>
 | radius   = 26.3 - 35.5<ref name=Lewis/>
 | luminosity  = 1,400<ref name=Lewis/>
 | temperature = 6,294<ref name=Lewis/>
 | metal_fe =
 | gravity  = {{val|2.4|0.2}}<ref name=ap28_3_335/>
 | rotational_velocity = 125<ref name="AAR20_1_51"/>
 | rotation = 16.60<ref name=Lewis/> [[day|d]]
 | age_myr  =
}}
{{Starbox catalog
 | names={{odlist | name=Sargas | name2=Girtab | name3=[[Gould designation|160 G.]] Scorpii | B=θ&nbsp;Sco | CD=−42°12312 | FK5=654 | HD=159532 | HIP=86228 | HR=6553 | SAO=228201 | CCDM=J17373−4300 }}<ref name=SIMBAD/>
}}
{{Starbox reference
| Simbad = tet+Sco
}}
{{Starbox end}}
'''Theta Scorpii''' ('''θ Scorpii''', abbreviated '''Theta Sco''', '''θ Sco''') is a [[binary star]] in the [[Southern celestial hemisphere|southern]] [[zodiac]] [[constellation]] of [[Scorpius]]. The [[apparent visual magnitude]] of this [[star]] is +1.87,<ref name=clpl4_99/> making it readily visible to the naked eye and one of the [[List of brightest stars|brightest stars]] in the [[night sky]]. It is sufficiently near that the distance can be measured directly using the [[stellar parallax|parallax]] technique and such measurements obtained during the ''[[Hipparcos]]'' mission yield an estimate of approximately {{Convert|101|pc|ly|abbr=off|lk=on|order=flip|sigfig=3}} from the [[Sun]].

The two components are designated '''θ Scorpii A''' (officially named '''Sargas''' {{IPAc-en|'|s|ɑr|g|æ|s}}, the traditional name for the system)<ref name=Kunitzsch/><ref name="IAU-LSN"/> and '''B'''.

==Nomenclature==
''θ Scorpii'' ([[Latinisation of names|Latinised]] to ''Theta Scorpii'') is the system's [[Bayer designation]]. The designations of the two components as ''Theta Scorpii A'' and ''B'' derive from the convention used by the Washington Multiplicity Catalog (WMC) for [[Star system|multiple star system]]s, and adopted by the [[International Astronomical Union]] (IAU).<ref name="planetnaming"/>

It bore the traditional name ''Sargas'', of [[Sumer]]ian origin.<ref name=burnham1978/> Another possible origin is [[Persian language|Persian]] for ''Arrow Head سر گز''. The name 'Sar Gaz' is used in [[Iran]] as a star name, and was used for timing irrigation water shares.<ref name="Nash"/> In 2016, the IAU organized a [[Working Group on Star Names]] (WGSN)<ref name="WGSN"/> to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire [[multiple star|multiple systems]].<ref name="TriRpt18"/>  It approved the name ''Sargas'' for the star θ Scorpii A on 21 August 2016 and it is now so included in the List of IAU-approved Star Names.<ref name="IAU-LSN"/>

In [[Chinese astronomy|Chinese]], {{lang|zh|尾宿}} ({{lang|zh-Latn|Wěi Xiù}}), meaning ''[[Tail (Chinese constellation)|Tail]]'', refers to an [[asterism (astronomy)|asterism]] consisting of Theta Scorpii, [[Epsilon Scorpii]], [[Zeta1 Scorpii|Zeta<sup>1</sup> Scorpii]] and [[Zeta2 Scorpii|Zeta<sup>2</sup> Scorpii]], [[Eta Scorpii]], [[Iota1 Scorpii|Iota<sup>1</sup> Scorpii]] and [[Iota2 Scorpii|Iota<sup>2</sup> Scorpii]], [[Kappa Scorpii]], [[Lambda Scorpii]], [[Mu1 Scorpii|Mu<sup>1</sup> Scorpii]] and [[Upsilon Scorpii]].<ref>{{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}}.</ref> Consequently, the [[Chinese star names|Chinese name]] for Theta Scorpii itself is {{lang|zh|尾宿五}} ({{lang|zh-Latn|Wěi Xiù wǔ}}), "the Fifth Star of Tail".<ref>{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ala_alz.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive|url=https://web.archive.org/web/20081025110153/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ala_alz.htm |date=2008-10-25 }}, Hong Kong Space Museum. Accessed on line November 23, 2010.</ref>

==Properties==
The primary (θ Scorpii A) is an [[stellar evolution|evolved]] [[bright giant]] star with a [[stellar classification]] of F0&nbsp;II.<ref name=houk1978/> With a mass 3.10 times that [[solar mass|of the Sun]], it is radiating 1,400<ref name=Lewis/> times as much luminosity [[solar luminosity|as the Sun]] from its [[stellar atmosphere|outer envelope]] at an [[effective temperature]] of 6,294&nbsp;K,<ref name=Lewis/> giving it the yellow-white-hued glow of an [[F-type star]]. This star is rotating rapidly, giving it an [[Oblate spheroid|oblate shape]] with an equatorial radius 33% larger than the polar radius. The equatorial radius is about {{solar radius|36|link=y}} while the polar radius is only about {{solar radius|26}}.  This rapid rotation suggests that it formed via the merger of a [[binary star]] system.<ref name=Lewis/>

A magnitude 5.36 companion has been reported at an [[angular separation]] of 6.470&nbsp;[[arcseconds]],<ref name=mnras389_2_869/> but subsequent observers have failed to detect it, so it probably does not exist. However, a secondary, designated θ Scorpii B, has been detected at an angular separation of 0.538&nbsp;arcseconds in 1991 by the Hipparcos satellite.<ref name=Lewis/>

==Modern legacy==
Theta Scorpii appears on the [[flag of Brazil]], symbolising the state of [[Alagoas]].<ref name=flag/>

== References ==
{{reflist|refs=

<ref name="Nash">{{cite conference
 | url=https://www.researchgate.net/publication/279529418
 | title=Traditional Timing of Qanat Water Shares
 | conference=International Conference on Traditional Knowledge for Water | date=2012
 | author=Nash, Harriet |display-authors=etal 
 | access-date=26 April 2017}}</ref>

<ref name="ayres2018">{{Cite journal |last=Ayres |first=Thomas R. |date=2018-02-20 |title=Cracking the Conundrum of F-Supergiant Coronae |journal=The Astrophysical Journal |volume=854 |issue=2 |pages=95 |arxiv=1802.02552 |bibcode=2018ApJ...854...95A |doi=10.3847/1538-4357/aaa6d7 |issn=0004-637X |doi-access=free}}</ref>

<ref name="WGSN">{{cite web
 | 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 }}</ref>

<ref name="TriRpt18">{{cite web | url=https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf | page=5 | title=WG Triennial Report (2015-2018) - Star Names |access-date=2018-07-14}}</ref>

<ref name=flag>{{cite web
|title=Astronomy of the Brazilian Flag
|url=https://flagspot.net/flags/br_astro.html
|publisher=Flags of the World
}}</ref>

<ref name="IAU-LSN">{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars |publisher=IAU.org |access-date=3 March 2018}}</ref>

<ref name=aaa474_2_653>{{cite journal | first=F. | last=van Leeuwen |date=November 2007 | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 |arxiv = 0708.1752 | s2cid=18759600 }}</ref>

<ref name=Anderson2012>{{cite journal
 | title=XHIP: An extended hipparcos compilation
 | last1=Anderson | first1=E. | last2=Francis | first2=Ch.
 | journal=Astronomy Letters
 | volume=38 | issue=5 | pages=331 | year=2012
 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015
 | arxiv=1108.4971 | s2cid=119257644 }}</ref>

<ref name=gcsrv>{{cite journal | last=Wilson | first=R. E. | date=1953 | title=General Catalogue of Stellar Radial Velocities | journal=Carnegie Institute Washington D.C. Publication | publisher=Carnegie Institute of Washington D.C. | bibcode=1953GCRV..C......0W }}</ref>

<ref name=clpl4_99>{{cite journal | last1=Johnson | display-authors=1 | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | pages=99 | date=1966 | bibcode=1966CoLPL...4...99J }}</ref>

<ref name=houk1978>{{cite journal | last1=Houk | first1=Nancy | title=Michigan catalogue of two-dimensional spectral types for the HD stars | journal=Ann Arbor: Dept. Of Astronomy | volume=2 | location=Ann Arbor | publisher=Departement of Astronomy, University of Michigan | date=1978 | bibcode=1978mcts.book.....H }}</ref>

<ref name=ap28_3_335>{{cite journal | first1=Z. A. | last1=Samedov | title=Investigation of the atmospheres of the stars ι1 Sco (F2 Ia) and θ Sco (F1 II) | journal=Astrophysics | volume=28 | issue=3 | pages=335–341 | doi=10.1007/BF01112969 |bibcode = 1988Ap.....28..335S | year=1988 | s2cid=119828317 }}</ref>

<ref name=mnras389_2_869>{{cite journal | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | title=A catalogue of multiplicity among bright stellar systems | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=389 | issue=2 | pages=869–879 |date=September 2008 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | bibcode=2008MNRAS.389..869E |arxiv = 0806.2878 | s2cid=14878976 }}</ref>

<ref name=SIMBAD>{{cite simbad | title=* tet Sco | access-date=2012-02-18 }}</ref>

<ref name=burnham1978>{{cite book | first1=Robert | last1=Burnham | title=Burnham's celestial handbook: an observer's guide to the universe beyond the solar system | volume=3 | series=Dover books explaining science | edition=2nd | publisher=Courier Dover Publications | date=1978 | isbn=0-486-23673-0 | page=1676 | url=https://books.google.com/books?id=PJzIt3SIlkUC&pg=PA1676 }}</ref>

<ref name=hog>{{cite journal|bibcode=2000A&A...355L..27H|title=The Tycho-2 catalogue of the 2.5 million brightest stars|journal=Astronomy and Astrophysics|volume=355|pages=L27|last1=Høg|first1=E.|last2=Fabricius|first2=C.|last3=Makarov|first3=V. V.|last4=Urban|first4=S.|last5=Corbin|first5=T.|last6=Wycoff|first6=G.|last7=Bastian|first7=U.|last8=Schwekendiek|first8=P.|last9=Wicenec|first9=A.|year=2000|doi=10.1888/0333750888/2862}}</ref>

<ref name=Lewis>{{cite journal | doi=10.1093/mnras/stac991 | arxiv=2204.02719 | bibcode=2022MNRAS.513.1129L | title=A study of the F-giant star θ Scorpii A: A post-merger rapid rotator? | year=2022 | last1=Lewis | first1=Fiona | last2=Bailey | first2=Jeremy | last3=Cotton | first3=Daniel V. | last4=Howarth | first4=Ian D. | last5=Kedziora-Chudczer | first5=Lucyna | last6=Van Leeuwen | first6=Floor | journal=Monthly Notices of the Royal Astronomical Society | volume=513 | issue=1 | pages=1129–1140 | doi-access=free }}</ref>

<ref name=Kunitzsch>{{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
}}</ref>

<ref name="planetnaming">{{cite arXiv |title=On the naming convention used for multiple star systems and extrasolar planets |date=2010 |eprint=1012.0707 |class=astro-ph.SR |last1= Hessman |first1=F. V. |last2= Dhillon |first2=V. S. |last3= Winget |first3=D. E. |last4= Schreiber |first4=M. R. |last5= Horne |first5=K. |last6= Marsh |first6=T. R. |last7= Guenther |first7=E. |last8= Schwope |first8=A. |last9= Heber |first9=U. }}</ref>

<ref name="AAR20_1_51">{{cite journal
 | last1     = van Belle
 | first1    = Gerard T.
 | title     = Interferometric observations of rapidly rotating stars
 | journal   = The Astronomy and Astrophysics Review
 | volume    = 20
 | issue     = 1
 | page      = 51
 | date      = March 2012
 | doi       = 10.1007/s00159-012-0051-2
 | bibcode   = 2012A&ARv..20...51V
 | arxiv     = 1204.2572
 | s2cid = 119273474
}}</ref>
}}

==External links==
*[https://web.archive.org/web/20060307183506/http://www.astro.uiuc.edu/~kaler/sow/girtab.html Theta Sco]

{{Stars of Scorpius}}

[[Category:Bayer objects|Scorpii, Theta]]
[[Category:Binary stars]]
[[Category:Scorpius]]
[[Category:F-type bright giants]]
[[Category:Stars with proper names|Sargas]]
[[Category:Henry Draper Catalogue objects|159532]]
[[Category:Hipparcos objects|086228]]
[[Category:Bright Star Catalogue objects|6553]]
[[Category:Gould objects|Scorpii, 160]]
[[Category:Durchmusterung objects]]