Robert's Quartet
The quartet is one of the best examples of compact galaxy groups. Because such groups contain four to eight galaxies in a very small region they are excellent laboratories for the study of galactic 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 is NGC 92, having the blue magnitude of 13.8. 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 and Barry F. Madore, who compiled A Catalogue of Southern Peculiar Galaxies and Associations in 1987. Arp and Madore named Robert's Quartet after Robert Freedman who generated many of the updated positions of galaxies in the catalogue.
Members
Name | Type | Distance from Sun (million ly) |
Magnitude |
---|---|---|---|
NGC 87 | IBm pec. | ~160 | +14.50 |
NGC 88 | SB(rs)a pec. | ~160 | +15.21 |
NGC 89 | SB0(s)a pec. | ~160 | +14.57 |
NGC 92 | SAa pec. | ~160 | +14.29 |
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/d9/Phot-34b-05-fullres.jpg/275px-Phot-34b-05-fullres.jpg)
See also
- Wild's Triplet
- Zwicky's Triplet
- Stephan's Quintet and NGC 7331 Group (Also known as the Deer Lick Group about half a degree northeast of Stephan's Quintet)
- Seyfert's Sextet
- Copeland Septet
References
- ^ Darling, David. "Robert's Quartet". David Darling. Retrieved 21 January 2019.
- ^ Herschel, John Frederick William (1847). Results of astronomical observations made during the years 1834, 5, 6, 7, 8, at the Cape of Good Hope: being the completion of a telescopic survey of the whole surface of the visible heavens, commenced in 1825. Vol. 1. London, United Kingdom: Smith, Elder and Co. p. 51. Bibcode:1847raom.book.....H.
- ^ "Cosmic Portrait of a Perturbed Family". European Southern Observatory. Retrieved 21 January 2019.
- ^ "NGC 92". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-24.
External links
- ESo: Cosmic Portrait of a Perturbed Family
- "What's In A Name?"
- Robert's Quartet on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images