Cepheus (abbr. Cep, gen. Cephei)
The King, father of Andromeda; a northern constellation, mostly circumpolar from as far south as latitude 30° N, with a noticeable quadrilateral shape made from Alpha, Beta, Iota, and Zeta. Cepheus contains several variable stars that are prototypes of their classes, the most important of which is Delta Cephei. VV Cep is a huge eclipsing binary of the Zeta Aurigae type, consisting of a red supergiant and a smaller blue companion in a 20.3-year orbit (magnitude range 4.7 to 5.4; R.A. 21h 56.7m, Dec. +63° 38'). There are also two interesting open clusters. NGC 6939 is a fine cluster of about 80 stars in a rich field that includes NGC 6946, a face-on spiral galaxy. It lies 2.5° south of Theta Cep and 2° southwest of Eta Cep (magnitude 7.8, diameter 7.8'; R.A. 20h 31.4m, Dec. +60° 38'). NGC 188 contains about 120 stars and is possibly the oldest known open cluster, with an age of about 5 billion years (magnitude 8.1; diameter 14'; distance 5,000 light-years; R.A. 00h 44.5m; Dec. +85° 20'). See below for details of the constellation's brightest stars.
Related categories NOTABLE STARS
NEBULAE AND STAR CLUSTERS
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