| NGC 681 | |
|---|---|
 legacy surveys image of NGC 681 | |
| Observation data (J2000epoch) | |
| Constellation | Cetus |
| Right ascension | 01h 49m 10.829s[1] |
| Declination | −10° 25′ 35.13″[1] |
| Redshift | 0.00587 ± 0.00002[1] |
| Heliocentric radial velocity | 1760.4 ± 6.6 km/s[1] |
| Distance | ~66.5 millionly (20.39 ± 1.45Mpc)[1] |
| Group orcluster | MCG -02-05-053 Group (LGG 33) |
| Apparent magnitude (V) | 12[2] |
| Characteristics | |
| Type | SAB(s)ab |
| Mass | 1.9×1010[3] M☉ |
| Mass/Light ratio | 3.6[3] M☉/L☉ |
| Size | ~29.07kpc (diameter)[1] |
| Apparent size (V) | 2.70 × 1.8arcmin[2][4] |
| Other designations | |
| IRAS 01467-1040,MCG -02-05-052,PGC 6671[5] | |
NGC 681 is anintermediate spiral galaxy in theconstellation ofCetus, located approximately 66.5 millionlight-years from Earth.[1][2][4]
NGC 681 is a member of the MCG -02-05-053 group (also known asLGG 33), which contains four galaxies, includingNGC 701 andIC 1738.[6]
NGC 681 was discovered by the German-born British astronomerWilliam Herschel on 28 November 1785 and was later also observed by William's son,John Herschel.[2]John Louis Emil Dreyer, compiler of the firstNew General Catalogue of Nebulae and Clusters of Stars, described NGC 681 as being a "pretty faint, considerably large, round, small (faint)star 90arcsec to [the] west" that becomes "gradually a little brighter [in the] middle".[2]
NGC 681 shares many structural similarities with the Sombrero Galaxy, M104, although it is smaller, less luminous, and less massive. Its thin, dustydisc is seen almost perfectly edge-on and features a small, very bright nucleus in the center of a very pronouncedbulge.[7] Distinctly unlike M104, NGC 681's disc contains manyH II regions, wherestar formation is likely to be occurring.[3][7] The galaxy has a mass of1.9×1010M☉, amass-to-light ratio of 3.6, and a spiral pattern which is asymmetrical.[3]
TheSIMBAD database lists NGC 681 as aSeyfert II Galaxy, i.e. it has aquasar-like nucleus with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, the host galaxy is clearly detectable.[8]
Onesupernova has been observed in NGC 681. SN 2024abup (type Ib/c, mag. 17.018) was discovered byATLAS on 22 November 2024.[9]
Media related toNGC 681 at Wikimedia Commons
