- Robert's Quartet
Galaxy cluster
name = Robert's Quartet
epoch=J2000
ra=RA|0|21|23.075
dec=DEC|-48|37.75|39.5
constellation = Phoenix
member_no = 4
brightest_member =NGC 92
other_names = AM 0018-0485Robert's Quartet is a compact
galaxy group approximately 160 millionlight-year s away in theconstellation Phoenix. It is a family of four very differentgalaxies in the process ofcolliding and merging . Its members areNGC 87 ,NGC 88 ,NGC 89 andNGC 92 , discovered byJohn Herschel in the1830 s.The quartet is one of the finest examples of compact groups of galaxies. Because such groups contain four to eight galaxies in a very small region, they are excellent laboratories for the study of galaxy interactions and their effects, in particular on the formation of stars. The quartet has a total visual magnitude of almost 13. The brightest member of the group has a magnitude of about 14. On the sky, the four galaxies are all within a circle of radius of 1.6 arcmin, corresponding to about 75,000 light-years. It was named by
Halton Arp andBarry F. Madore , who compiled "A Catalogue of Southern Peculiar Galaxies and Associations" in 1987.Members
External links
* [http://www.eso.org/outreach/press-rel/pr-2005/phot-34-05.html ESo: Cosmic Portrait of a Perturbed Family]
* [http://www.asnsw.com/universe/2001/wian-0901.htm "What's In A Name?"]
*ee also
*
Stephan's Quintet
*Seyfert's Sextet
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