NGC 457

From Wikipedia, the free encyclopedia
Jump to: navigation, search
NGC 457
NGC457.jpg
Observation data (J2000.0 epoch)
Constellation Cassiopeia
Right ascension 01h 19m 32.6s
Declination +58° 17′ 27″
Distance 7.922 kly (2.429[1] kpc)
Apparent magnitude (V) 6.4[2]
Apparent dimensions (V) 13.0′[2]
Physical characteristics
Mass M
Other designations Cr 12, Mel 7, OCL 321, Lund 43, H VII-42, h 97, GC 256,[2] Caldwell 13, Owl Cluster, ET Cluster
See also: Open cluster, List of open clusters

NGC 457 (also known as the Owl Cluster, the ET Cluster, or Caldwell 13) is an open star cluster in the constellation Cassiopeia. It was discovered by William Herschel in 1787,[2] and lies over 7,900 light years away from the Sun. It has an estimated age of 21 million years.[1] The cluster is sometimes referred by amateur astronomers as the Owl Cluster, Kachina Doll Cluster,[2] the ET Cluster (due to its resemblance to the movie character) or the "Skiing Cluster". Two bright stars, magnitude 5 Phi-1 Cassiopeiae and magnitude 7 Phi-2 Cassiopeiae can be imagined as eyes. The cluster features a rich field of about 150 stars of magnitudes 12-15.[2]

References[edit]

  1. ^ a b Frinchaboy, Peter M.; et al. (2008). "Open Clusters as Galactic Disk Tracers. I. Project Motivation, Cluster Membership, and Bulk Three-Dimensional Kinematics". The Astronomical Journal 136: 118–145. arXiv:0804.4630. Bibcode:2008AJ....136..118F. doi:10.1088/0004-6256/136/1/118.  See table I, p. 12.
  2. ^ a b c d e f "NGC 457". The NGC/IC Project Database. Retrieved 2012-05-09. 

External links[edit]