NGC 457
Open star cluster in the constellation Cassiopeia
NGC 457 is an open cluster of stars in the northern constellation of Cassiopeia. Alternatively, it is designated Caldwell 13, and known as the Dragonfly Cluster, E.T. Cluster, Owl Cluster, Kachina Doll Cluster or Phi Cassiopeiae Cluster. It was discovered by German-British astronomer William Herschel on August 18, 1780, with a 6.2 inch reflector telescope, and catalogued as VII 42. This is an easy target for amateur astronomers, and can be seen even with small telescopes in light-polluted skies.
01Characteristics
It lies over 7,900 light years away from the Sun. It has an estimated age of 21 million years. The cluster is sometimes referred by amateur astronomers as the Owl Cluster or the E.T. Cluster (due to its resemblance to the movie character). Two bright stars Phi Cassiopeiae (magnitude 5 and spectral type F0) and HD 7902 (magnitude 7) can be imagined as eyes. It is not yet clear if Phi Cassiopeiae is a member of the cluster, and if it is, then it would be one of the brightest stars known, surpassing Rigel in luminosity. For comparison, the Sun at the same distance as Phi Cassiopeiae would shine at just 17.3 magnitude. The next brightest star is the red supergiant variable star V466 Cassiopeiae. The cluster features a rich field of about 150 stars of magnitude 9-13. About 60 stars have been identified as true members of the cluster.
Sources and credits
This article is adapted from the Wikipedia article “NGC 457”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- BGC 457Cluster.png by Chuck Ayoub, CC0
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