{{short description|Multiple star system in the constellation Hercules}} {{Starbox begin | name=δ Herculis }} {{Starbox image | image= {{Location mark |image=Hercules constellation map.svg|alt=|float=center|width=240 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=δ Herculis |x=586|y=666 }} |caption=Location of δ Herculis (circled) }} {{Starbox observe | epoch=J2000 | ra={{RA|17|15|01.9106}}<ref name="SIMBAD"/> | dec={{DEC|+24|50|21.135}}<ref name="SIMBAD"/> | appmag_v=3.126<ref name="SIMBAD"/> | constell=Hercules }} {{Starbox character | type=main sequence<ref name="KALER"/> | class=A3IV<ref name="SIMBAD" /> | b-v=+0.08<ref name="MERMILLIOD"/> | u-b=+0.7<ref name="MERMILLIOD"/> | variable= }} {{Starbox astrometry | radial_v=−40.0<ref name="SIMBAD"/> | prop_mo_ra=−21.14<ref name="SIMBAD"/> | prop_mo_dec=−157.68<ref name="SIMBAD"/> | parallax=43.41 | p_error=0.15 | parallax_footnote=<ref name="LEEUWEN"/> | absmag_v=+1.31<ref name=Anderson2012/> }} {{Starbox detail | component1=Aa | mass=2.4<ref name=aass85_3_1015/> | radius=2.2<ref name=aass85_3_1015/> | luminosity=38<ref name=aass85_3_1015/> | gravity=4.11<ref name=aass85_3_1015/> | temperature={{val|fmt=commas|9,620|350}}<ref name=aass85_3_1015/> | metal_fe= | rotational_velocity=270<ref name="KALER"/> | age_myr=370<ref name="KALER"/> | component2=Ab | mass2=1.6<ref name="KALER"/> | temperature2=7,500<ref name="KALER"/> | luminosity2=6.8<ref name="KALER"/> | radius2=1.5<ref name="KALER"/> }} {{Starbox catalog | names = Sarin, δ Her, 65 Her, BD+25°3221, CCDM J17151+2451A, FK5 641, GC 23294, HD 156164, HIP 84379, HR 6410, SAO 84951 }} {{Starbox reference | Simbad=HD+156164 }} {{Starbox end}}
'''Delta Herculis''' ('''δ Herculis''', abbreviated '''Delta Her''', '''δ Her''') is a spectroscopic binary in the constellation of Hercules. Its light produces to us apparent magnitude 3.12, as such the third-brightest star in the large, fairly dim constellation. Based on parallax measurement taken during the Hipparcos mission, it is approximately {{convert|23.1|pc|ly|abbr=off|lk=on}} from the Sun.
==Companions== Delta Herculis consists of a binary pair, designated Delta Herculis A, together with three optical companions, suffixed B, C and D.<ref name="WDS">{{cite web | url=http://ad.usno.navy.mil/wds/ | title=Washington Double Star Catalog | publisher=United States Naval Observatory | access-date=2 January 2018 | archive-url=https://web.archive.org/web/20110214155533/http://ad.usno.navy.mil/wds/ | archive-date=14 February 2011 | url-status=dead }}</ref> The angular separation between the main component A and the component B, which has a magnitude of 8.74, is 8.5 arcseconds [https://theskylive.com/sky/stars/sarin-delta-herculis-star].
A's components are designated Delta Herculis Aa (officially named '''Sarin''' {{IPAc-en|'|s|ɛər|I|n}}, the traditional name of the system)<ref name="IAU-LSN">{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars | publisher=IAU.org | access-date=16 December 2017 | archive-date=10 March 2025 | archive-url=https://web.archive.org/web/20250310063743/https://www.iau.org/public/themes/naming_stars/ | url-status=dead }}</ref> and Ab.
==Nomenclature==
''δ Herculis'' (Latinised to ''Delta Herculis'') is the system's Bayer designation. The designations of the four constituents as ''Delta Herculis A'', ''B'', ''C'' and ''D'', and those of ''A's'' components - ''Delta Herculis Aa'' 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).<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>
It bore the traditional name ''Sarin''.<ref name="BBC1"/><ref name="WIKISKY"/> In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)<ref name="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=. | archive-date=26 June 2019 | archive-url=https://web.archive.org/web/20190626015649/https://www.iau.org/science/scientific_bodies/working_groups/280/ | url-status=dead }}</ref> to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.<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 | archive-date=2019-08-23 | archive-url=https://web.archive.org/web/20190823174756/https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf | url-status=dead }}</ref> It approved the name ''Sarin'' for the component Delta Herculis Aa on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.<ref name="IAU-LSN"/>
In the catalogue of stars in the ''Calendarium'' of Al Achsasi al Mouakket, this star was designated ''Menkib al Jathi al Aisr'', which was translated into Latin as ''Humerus Sinister Ingeniculi'', meaning ''kneeler's left shoulder''.<ref name=mnras55_429/>
In Chinese, {{lang|zh|天市左垣}} ({{lang|zh-Latn|Tiān Shì Zuǒ Yuán}}), meaning ''Left Wall of Heavenly Market Enclosure'', refers to an asterism which represents eleven old states in China which is marking the left borderline of the enclosure, consisting of Delta Herculis, Lambda Herculis, Mu Herculis, Omicron Herculis, 112 Herculis, Zeta Aquilae, Theta<sup>1</sup> Serpentis, Eta Serpentis, Nu Ophiuchi, Xi Serpentis and Eta Ophiuchi.<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 name for Delta Herculis itself is {{lang|zh|天市左垣一}} ({{lang|zh-Latn|Tiān Shì Zuǒ Yuán yī}}, {{langx|en|the First Star of Left Wall of Heavenly Market Enclosure}}), and represents the state of Wei (魏),<ref>{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_c_d.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive |url=https://web.archive.org/web/20090929163750/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_c_d.htm |date=September 29, 2009 }}, Hong Kong Space Museum. Accessed on line November 23, 2010.</ref><ref>{{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 |url=https://web.archive.org/web/20100810114313/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm#HeavenlyMarketEnclosure |date=August 10, 2010 }}, Hong Kong Space Museum. Accessed on line November 23, 2010.</ref> together with 33 Capricorni, according to Ian Ridpath version<ref>[http://www.ianridpath.com/startales/capricornus.htm Ian Ridpath's Startales - Capricornus the Sea Goat]</ref> or Phi Capricorni and Chi Capricorni in R.H. Allen's version<ref>[https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Capricornus*.html Star Names - R.H.Allen p.142]</ref> in ''Twelve States'' (asterism).
== Properties ==
Delta Herculis A presents as an A-type subgiant with a stellar classification of A3IV. It has both a mass and radius that are roughly two times solar yielding a total luminosity of about {{Solar luminosity|link=y|18.5}}<ref name="KALER"/> The secondary is about 1.3 magnitudes fainter.<ref name="WDS"/>
==See also== *Lists of stars in the constellation Hercules *Class A Stars
== References == <references> <ref name="LEEUWEN">{{cite journal |title=Hipparcos, the New Reduction |last1=van Leeuwen |first1=F. |date=November 2007 |pages=653–664 |issue=2 |volume=474 |doi=10.1051/0004-6361:20078357 |journal=Astronomy and Astrophysics |bibcode=2007A&A...474..653V |arxiv=0708.1752|s2cid=18759600 }}</ref>
<ref name=Anderson2012>{{citation | 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 | postscript=. }}</ref>
<ref name="MERMILLIOD">{{citation |author=Mermilliod, J.-C. |title=Compilation of Eggen's UBV data, transformed to UBV (unpublished) |journal=Catalogue of Eggen's UBV Data |date=1986 |publisher=SIMBAD |bibcode=1986EgUBV........0M }}</ref>
<ref name="SIMBAD">{{citation | url=http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Delta+her | work=SIMBAD | title=del Her -- Star in double system | publisher =Centre de Données astronomiques de Strasbourg | access-date = 2010-11-17 }}</ref>
<ref name=aass85_3_1015>{{citation | last1=Malagnini | first1=M. L. | last2=Morossi | first2=C. | title=Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars | journal=Astronomy and Astrophysics Supplement Series | volume=85 | issue=3 | pages=1015–1019 |date=November 1990 | bibcode=1990A&AS...85.1015M }}</ref>
<ref name="KALER">{{citation | title=DELTA HER (Delta Herculis) | work=Stars | publisher=University of Illinois | first1=James B. | last1=Kaler | url=http://stars.astro.illinois.edu/sow/deltaher.html | access-date=2010-11-17 }}</ref>
<ref name="BBC1">{{citation | title=Constellations: Hercules 'the Strongman' | publisher=The BBC (British Broadcasting Corporation) | first1=Kurt | last1=Vonnegut | url=https://www.bbc.co.uk/dna/h2g2/A29778916 | access-date=2010-11-17 }}</ref>
<ref name="WIKISKY">{{citation | title=δ Her (Sarin) | publisher=Wikisky.org | url=http://server1.wikisky.org/starview?object_type=1&object_id=403&object_name=Sarin | access-date=2010-11-17 }}</ref>
<ref name=mnras55_429>{{citation | last=Knobel | first=E. B. | title=Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket | journal=Monthly Notices of the Royal Astronomical Society | volume=55 | page=429 |date=June 1895 | bibcode=1895MNRAS..55..429K | doi=10.1093/mnras/55.8.429| doi-access=free }}</ref> </references>
==External links== *Jim Kaler's Stars, University of Illinois: [http://stars.astro.illinois.edu/sow/deltaher.html DELTA HER (Delta Herculis)] *An Atlas of the Universe: [http://www.atlasoftheuniverse.com/orbits.html Multiple Star Orbits]
{{Stars of Hercules}} {{Sky|17|15|01.910|+|24|50|21.135|1000000}}
Category:Hercules (constellation) Herculis, Delta Sarin Herculis, 065 Category:A-type main-sequence stars 084379 6410 156164 Category:Durchmusterung objects