Delta Corvi is a star in the southern constellation of Corvus. It has the proper name Algorab, pronounced ; Delta Corvi is its Bayer designation. With an apparent visual magnitude of +2.962, this star is visible to the naked eye. Based on parallax measurements, it is located at a distance of from the Sun The star is receding with a line of sight velocity component of +9 km/s.
Nomenclature
δ Corvi (Latinised to Delta Corvi) is the star's Bayer designation, which is abbreviated Delta Crv or δ Crv.
It bore the traditional name Algorab derived from Arabic الغراب al-ghuraab, meaning 'the crow'. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included Algorab for this star.
In Chinese, (), meaning Chariot, refers to an asterism consisting of Delta Corvi, Gamma Corvi, Epsilon Corvi and Beta Corvi. 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, . Consequently, Delta 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.
Stellar properties
Delta Corvi has more than 2.7 times the mass of the Sun, which is causing it to radiate a much higher energy output—roughly 69 times the Sun's luminosity. The effective temperature of the outer atmosphere is , giving it the white hue of an A-type star. The spectrum matches a stellar classification of . However, it is more luminous—65 to 70 times that of the Sun—than it would be if it were on the main sequence. Hence it is either a subgiant star around 260 million years old that has nearly exhausted the supply of hydrogen at its core and is in the process of evolving away from the main sequence of stars like the Sun, or a pre-main-sequence star around 3.2 million years old that has not completely condensed and settled on the main sequence.
In 1823, Delta Corvi was found to be a wide double star by British astronomers James South and John Herschel. Since that time, the position of the two stars with respect to each other has not changed. The magnitude 9.3 companion, HR 4757 B, with a classification of K2Ve, is at an angular separation of 24.2 arcseconds along a position angle of 214°. Although the two stars share a common proper motion, the significant differences in their estimated ages suggests that they may not be physically connected.
A 2006 study found that Delta Corvi displayed no excess infrared emission that would otherwise suggest the presence of circumstellar matter; however, warm interstellar dust was detected in a 2014 study.
Delta Corvi may be a binary star system. There is a star that shares a similar proper motion and thus is believed to be gravitationally bound. This possible companion has a projected separation of 640 astronomical units and around 0.7 times the mass and 0.8 times the radius of the Sun.
In culture USS Algorab (AKA-8) was a United States Navy ship named after the star.
Algorab is one of the Behenian fixed stars.
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