Caldwell 89
NGC 6087 (also known as Caldwell 89 or the S Normae Cluster) is an open cluster of 40 or more stars centered on the Cepheid variable S Normae in the constellation Norma. At a distance of about 3500 ly and covering a field of almost one quarter of a degree, the stars range from seventh- to eleventh-magnitude, the brightest being 6.5 magnitude S Normae. The aggregate visual magnitude of the cluster is about 5.4.
Spectral analysis of the radial motion of the stars confirm that S Normae is a member of the cluster, and the period/luminosity relationship of Cepheid variables allows the distance to be determined with confidence.
References
- ^ "NGC 6087". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2007-04-18.
- ^ Burnham's Celestial Handbook gives the number 40, though other studies go as high as 349; see Stephen James O'Meara, The Caldwell Objects, Cambridge University Press, 2002, p. 351.
- ^ A. U. Landolt (1964). "The Galactic Cluster NGC 6087". Astrophysical Journal Supplement. 8: 329–351. Bibcode:1964ApJS....8..329L. doi:10.1086/190092.
External links
Media related to NGC 6087 at Wikimedia Commons- NGC 6087 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
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