| NGC 6331 | |
|---|---|
 SDSS image of NGC 6331 | |
| Observation data (J2000epoch) | |
| Constellation | Ursa Minor |
| Right ascension | 17h 03m 35.97s |
| Declination | +78d 37m 44.40s |
| Redshift | 0.053614 0.00150 |
| Heliocentric radial velocity | 17,570km/s |
| Distance | 737Mly (226Mpc) |
| Group orcluster | Abell 2256 |
| Apparent magnitude (V) | 14.4 |
| Characteristics | |
| Type | E |
| Size | 345,000ly |
| Other designations | |
| PGC 84830,2MASX J17033591+7837435,SDSS J170335.88+783744.0, NSA 167203, WBL 631-001,CGCG 355-024,MCG +013-12-015 | |
NGC 6331 is a type E[1]elliptical galaxy located in theUrsa Minor constellation.[2][1] It is located 737 million light-years from theSolar System[3] and was discovered by German-BritishastronomerWilliam Herschel on December 20, 1797, utilizing an 18.7-inch f/13 spectrumtelescope[4] but also observed byGuillaume Bigourdan.[5]
With an approximatediameter of 345,000 light-years, NGC 6331 is well considered one of thelargest galaxies.[3] It is the brightest group member ofAbell 2256 and first in 6' string to the east, making up of 6 galaxies.[6] NGC 6331 also makes up a part of the galactic triplet CGCG 355-024[7] which comprises two other elliptical galaxies in the cluster, CGCG 355-024 NED03 (PGC 59513)[8] and CGCG 355-024 NED01 (PGC 84827).[9]
