Gamma Corvi

Template:Short description Template:Starbox begin Template:Starbox image Template:Starbox observe Template:Starbox character Template:Starbox astrometry Template:Starbox detail Template:Starbox catalog Template:Starbox reference Template:Starbox end Gamma Corvi (γ Corvi, abbreviated Gamma Crv, γ Crv) is a binary star and the brightest star in the southern constellation of Corvus, having an apparent visual magnitude of 2.59.<ref name=kalergamma>Template:Citation</ref> The system's two components are designated Gamma Corvi A (officially named Gienah Template:IPAc-en, traditionally the name of the system)<ref name=Kunitzsch>Template:Cite book</ref><ref name="IAU-LSN">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and Gamma Corvi B, whose magnitude is 9.7 and which is 1.1 arcseconds away from Gamma Corvi A.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The distance to this system has been measured directly using the parallax technique, yielding an estimated Template:Convert from the Sun.<ref name=aaa474_2_653/>

Nomenclature

γ Corvi (Latinised to Gamma Corvi) is the system's Bayer designation. The designation of the components – Gamma Corvi A and B – derives 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">Template:Cite arXiv</ref>

Gamma Corvi bore the traditional name of Gienah derived from Arabic, from Ulugh Beg's الجناح الغراب اليمن al-janāħ al-ghirāb al-yaman, meaning "the right wing of the crow", although on modern charts it marks the left wing.<ref name=hinkley1899>Template:Citation</ref> The star Epsilon Cygni also bore this traditional name and Gamma Corvi was referred to as Gienah Corvi or Gienah Ghurab to distinguish it from this star in Cygnus.

In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)<ref name="WGSN">Template:Citation</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">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It approved the name Gienah for the component Gamma Corvi A on 6 November 2016 and Aljanah for Epsilon Cygni Aa on 30 June 2017. They are both now so included in the List of IAU-approved Star Names.<ref name="IAU-LSN"/>

Al-janāħ al-ghirāb al-yaman or Djenah al Ghyrab al Eymen appeared in the catalog of stars in the Calendarium of Al Achsasi Al Mouakket, which was translated into Latin as Dextra ala Corvi.<ref name=mnras55_429/>

In Chinese, {{#invoke:Lang|lang}} ({{#invoke:Lang|lang}}), meaning Chariot (asterism), refers to an asterism consisting of Gamma Corvi, Epsilon Corvi, Delta Corvi and Beta Corvi.<ref>Template:In lang 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Template:ISBN.</ref> Consequently, Gamma Corvi itself is known as {{#invoke:Lang|lang}} ({{#invoke:Lang|lang}}, Template:Langx).<ref>Template:In lang 香港太空館 – 研究資源 – 亮星中英對照表 Template:Webarchive, Hong Kong Space Museum. Accessed on line November 23, 2010.</ref>

Properties

Gamma Corvi A is a giant star with a stellar classification of B8 III<ref name=houk1978/><ref name=csaao8/> and has approximately 4.2 times the mass of the Sun<ref name=apj736_2_89/> and 4.1 times the radius of the Sun.<ref name=TESS/> It has an effective temperature of 12,000 K,<ref name=aaa320_580/> two times hotter than the Sun, giving it the typical blue-white hue of late B-type stars.<ref name=csiro/> The spectrum of this star displays an anomalously higher than normal abundance of the elements mercury and manganese, making this a Mercury-manganese star.<ref name=aaa447_2_685/> However, there are other elements that show large over or under abundances.<ref name=aaa320_580/> This chemical peculiarity in an otherwise stable stellar atmosphere is most likely caused by separation of the elements through diffusion and gravitational settling.<ref name=aaa447_2_685/>

It has a confirmed stellar companion with a mass of about 0.8 times the Sun's, which may be orbiting at a separation of around 50 AU over a 158-year period.<ref name=apj736_2_89/> The photometry for Gamma Corvi B suggests a stellar classification in the range K5–M5 V.<ref name=aj133_2_545/>