NGC 7331
| NGC 7331 | |
|---|---|
| 300px
Taken by Vicent Peris using the 3.5 meter telescope at the Calar Alto Observatory in southern Spain.
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| Observation data (J2000 epoch) | |
| Constellation | Pegasus |
| Right ascension | 22h 37m 04.1s[1] |
| Declination | +34° 24′ 56″[1] |
| Redshift | 816 ± 1 km/s[1] |
| Distance | 40 ± 3 e6ly (12.2 ± 1.0 Mpc)[2] |
| Type | SA(s)b[1] |
| Apparent dimensions (V) | 10′.5 × 3′.7[1] |
| Apparent magnitude (V) | +10.4[1] |
| Other designations | |
| UGC 12113, PGC 69327,[1] Caldwell 30 | |
NGC 7331 (also known as Caldwell 30) is a spiral galaxy about 40 million light-years (12 Mpc) away in the constellation Pegasus. It was discovered by William Herschel in 1784.[3] NGC 7331 is the brightest member of the NGC 7331 Group of galaxies.
The galaxy is similar in size and structure to the galaxy we inhabit, and is often referred to as "the Milky Way's twin",[4] although recent discoveries regarding the structure of the Milky Way may call this similarity into doubt.[5]
Retrograde bulge
In spiral galaxies the central bulge typically co-rotates with the disk but the bulge in the galaxy NGC 7331 is rotating in the opposite direction to the rest of the disk.[6] The current bulge may have formed from infalling material, however if it has been there since the formation of the galaxy then it would be difficult to explain how such a situation arose.
Supernova
SN 1959D, a Type IIL supernova,[7] is the only supernova that has been identified within NGC 7331.[1] The supernova was discovered by Milton Humason and H. S. Gates in a survey at Palomar Observatory.[8]
Possible 2014 Supernova [9]
See also
- M94 – another galaxy with a prominent starburst ring
- NGC 1512 – another galaxy with a prominent starburst ring
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ The NGC/IC Project : NGC Discoverers List by Bob Erdmann.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ A Counter-rotating Bulge in the Sb Galaxy NGC 7331 , F. Prada, C. Gutierrez, R.F. Peletier, C.D. McKeith, THE ASTROPHYSICAL JOURNAL, 463 :L9–L12, 1996 May 20
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
External links
- Calar Alto Observatory – NGC 7331
- APOD (2004-07-01) – "A Galaxy So Inclined"
- SST – "Morphology of Our Galaxy's 'Twin'"
- NGC 7331 at the astro-photography site of Mr. T. Yoshida
- NGC7331 at W. Kloehr Astrophotography
- NGC 7331 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
Coordinates: 
22h 37m 04.1s, +34° 24′ 56″
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