1911 Encyclopædia Britannica/Centaurus

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CENTAURUS (“The Centaur”), in astronomy, a constellation of the southern hemisphere, mentioned by Eudoxus (4th century B.C.) and Aratus (3rd century B.C.), Ptolemy catalogued thirty-seven stars in it. α-Centauri is a splendid binary star. Its components are of the 1st magnitude, and revolve in a period of eighty-one years; and since its parallax is 0.75″, it is the nearest star to the earth; ω-Centauri, the finest globular star-cluster in the heavens, consists of about 6000 stars in a space of about 20′ diameter, of which about 125 variables have been examined. Nova Centauri, a “new” star, was discovered in 1895 by Mrs Fleming in photographs taken at Harvard.