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Alphaulka, Beta Gruis

The second brightest star in the constellation of Grus, the Crane (after Alnair lying directly to the west). Gruid is a reddish star that appears southward of bright Fomalhaut in the sky, and indeed historically Gruid and Alnair were seen as part of Fomalhaut's constellation of Piscis Austrinus, with the two stars forming the Southern Fish's tail. Now that they fall within the boundaries of Grus, Gruid and Alnair are usually seen as representing the two feet of the Crane.

Gruid (sometimes known as Alphaulka) is a red giant star, 150 times the diameter of the Sun or more, but far less dense and somewhat cooler. Its brightness is not fixed: every thirty-seven days it displays a series of irregular shifts in its luminosity that can see its brightness change by a third of a magnitude or more.


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