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Delta Corvi, 7 Corvi

The main body of Corvus, the constellation of the Crow, is made up of a quadrangle of four stars, sandwiched between the much larger constellations of Virgo to the north and Hydra to the south. The northeastern corner of this quadrangle is marked by Algorab, the third brightest of the four stars. Its name comes from the Arabic for 'the Crow', and the name Algorab was historically also used for neighbouring Gamma Corvi, the star now more usually called Gienah (or Gienah Ghurab or Gienah Corvi).

Algorab is a hot blue-white star some eighty-seven light years from the Solar System. Its spectral type places it on the border between blue B-type and white A-type stars, and sources differ on which classification is to be preferred. The star is somewhat larger than the Sun (at some two to three times the Sun's diameter) but generates a great deal more heat and light.

The nature of the Algorab system is not completely clear, but the primary star appears to have tiny orange dwarf companion in a distant, millennia-long orbit, and there are also indications of a circumstellar disc of hot material within the system. The exceptionally slow orbit of the dwarf star (designated Algorab B) means that its identity as a binary companion to Algorab A is not yet certain, and the two stars conceivably represent an optical double rather than forming a true binary pair.


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