NGC 681
| NGC 681 | |
|---|---|
 legacy surveys image of NGC 681 | |
| Observation data (J2000 epoch) | |
| 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 million ly (20.39 ± 1.45 Mpc)[1] |
| Group or cluster | 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 | ~29.07 kpc (diameter)[1] |
| Apparent size (V) | 2.70 × 1.8 arcmin[2][4] |
| Other designations | |
| IRAS 01467-1040, MCG -02-05-052, PGC 6671[5] | |
NGC 681 is an intermediate spiral galaxy in the constellation of Cetus, located approximately 66.5 million light-years from Earth.[1][2][4]
NGC 681 is a member of the MCG -02-05-053 group (also known as LGG 33), which contains four galaxies, including NGC 701 and IC 1738.[6]
Observation history
[edit]NGC 681 was discovered by the German-born British astronomer William Herschel on 28 November 1785 and was later also observed by William's son, John Herschel.[2] John Louis Emil Dreyer, compiler of the first New General Catalogue of Nebulae and Clusters of Stars, described NGC 681 as being a "pretty faint, considerably large, round, small (faint) star 90 arcsec to [the] west" that becomes "gradually a little brighter [in the] middle".[2]
Physical characteristics
[edit]NGC 681 shares many structural similarities with the Sombrero Galaxy, M104, although it is smaller, less luminous, and less massive. Its thin, dusty disc is seen almost perfectly edge-on and features a small, very bright nucleus in the center of a very pronounced bulge.[7] Distinctly unlike M104, NGC 681's disc contains many H II regions, where star formation is likely to be occurring.[3][7] The galaxy has a mass of 1.9×1010 M☉, a mass-to-light ratio of 3.6 , and a spiral pattern which is asymmetrical.[3]
The SIMBAD database lists NGC 681 as a Seyfert II Galaxy, i.e. it has a quasar-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]
Image gallery
[edit]-
SDSS image of NGC 681
See also
[edit]References
[edit]- ^ a b c d e f g "NGC 681 NASA/IPAC Extragalactic Database Results". ned.ipac.caltech.edu. Retrieved November 2, 2018.
- ^ a b c d e "New General Catalog Objects: NGC 650 - 699". cseligman.com. Retrieved November 2, 2018.
- ^ a b c d Burbridge, E. M.; G.R., Burbridge; Prendergast, K.H. (1965). "Rotation and Mass of the SA Galaxy, NGC 681". Astrophysical Journal. 142: 154–159. Bibcode:1965ApJ...142..154B. doi:10.1086/148270. hdl:2060/19650010085.
- ^ a b "Revised NGC Data for NGC 681". spider.seds.org. Retrieved November 2, 2018.
- ^ "NGC 681". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-02-19.
- ^ Garcia, A. M. (1993). "General study of group membership. II. Determination of nearby groups". Astronomy and Astrophysics Supplement Series. 100: 47. Bibcode:1993A&AS..100...47G.
- ^ a b Faber, S. M.; Balick, B.; Gallagher, J. S.; Knapp, G. R. (1977). "The neutral hydrogen content, stellar rotation curve, and mass-to-light ratio of NGC 4594, the "Sombrero" galaxy". The Astrophysical Journal. 214: 383–389. Bibcode:1977ApJ...214..383F. doi:10.1086/155260. ISSN 0004-637X.
- ^ "NGC 691". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 23 November 2024.
External links
[edit]
Media related to NGC 681 at Wikimedia Commons
