Gamma Corvi (γ Corvi, abbreviated Gamma Crv, γ Crv) is a

binary star A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

and the brightest star in the southern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Corvus ''Corvus'' is a widely distributed genus of passerine birds ranging from medium-sized to large-sized in the family Corvidae. It includes species commonly known as crows, ravens, and rooks. The species commonly encountered in Europe are the car ...

, having an

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light ca ...

of 2.59. The system's two components are designated Gamma Corvi A (officially named Gienah , traditionally the name of the system) and Gamma Corvi B, whose magnitude is 9.7 and which is 1.1 arcseconds away from Gamma Corvi A. The distance to this system has been measured directly using the

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

technique, yielding an estimated from the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

Nomenclature

''γ Corvi'' ( Latinised to ''Gamma Corvi'') is the system's

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...

. The designation of the components – ''Gamma Corvi A'' and ''B'' – derives from the convention used by the Washington Multiplicity Catalog (WMC) for

multiple star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. It may sometimes be used to refer to a single star. A large group of stars bound by gravitation is generally called a ''st ...

s, and adopted by the

International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

(IAU). Gamma Corvi bore the traditional name of ''Gienah'' derived from

Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

, from

Ulugh Beg Mīrzā Muhammad Tarāghāy bin Shāhrukh (; ), better known as Ulugh Beg (; 22 March 1394 – 27 October 1449), was a Timurid sultan, as well as an astronomer and mathematician. Ulugh Beg was notable for his work in astronomy-related ma ...

'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. 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

organized a

Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...

(WGSN) to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. 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. ''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 Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

as ''Dextra ala Corvi''. In Chinese, (), meaning '' Chariot (asterism)'', refers to an asterism consisting of Gamma Corvi,

Epsilon Corvi Epsilon Corvi (ε Crv, ε Corvi) is a star in the southern constellation of Corvus. It has the traditional name Minkar , from Arabic منقار ''minqar'' meaning "beak f the crow The apparent visual magnitude is +3.0 and it is located ...

Delta Corvi Delta Corvi (δ Corvi, abbreviated Delta Crv, δ Crv), also named Algorab , is a third magnitude star at a distance of from the Sun in the southern constellation of Corvus. Nomenclature ''δ Corvi'' ( Latinised to ''Delta Corvi'') is t ...

and

Beta Corvi Beta Corvi or β Corvi, officially named Kraz (), is the second-brightest star in the southern constellation of Corvus with an apparent visual magnitude of 2.647. Based on parallax measurements obtained during the Hipparcos miss ...

. Consequently, Gamma Corvi itself is known as (, ).香港太空館 – 研究資源 – 亮星中英對照表
, Hong Kong Space Museum. Accessed on line November 23, 2010.

Properties

Gamma Corvi A is a

giant star A giant star has a substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature. They lie above the main sequence (luminosity class V in the Yerkes spectral classification) on the Hertzsp ...

with a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction gratin ...

of B8 III and has approximately 4.2 times the

mass of the Sun The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies a ...

and 4.1 times the

radius of the Sun Solar radius is a unit of distance used to express the size of objects in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: 1\,R_ = 6.957\ti ...

. It has an

effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...

of 12,000 K, two times hotter than the Sun, giving it the typical blue-white hue of late

B-type star In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...

s. The

spectrum A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...

of this star displays an anomalously higher than normal abundance of the elements mercury and

manganese Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition m ...

, making this a

Mercury-manganese star A mercury-manganese star (also HgMn star) is a type of chemically peculiar star with a prominent spectral line at 398.4 nm, due to absorption from ionized mercury. These stars are of spectral type B8, B9, or A0, corresponding to surface temper ...

. However, there are other elements that show large over or under abundances. This chemical peculiarity in an otherwise stable stellar atmosphere is most likely caused by separation of the elements through diffusion and gravitational settling. 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. The photometry for Gamma Corvi B suggests a stellar classification in the range K5–M5 V.

References

{{Stars of Corvus Corvi, Gamma B-type giants Corvus (constellation) Gienah Binary stars Corvi, 04 059803 106625 4662 Durchmusterung objects