NGC 4656/57
Galaxy NGC 4656/57 |
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GALEX image of NGC 4656/57; the entry NGC 4657 is based on the slightly offset structure in the upper left corner of the image. | |
AladinLite | |
Constellation | Hunting dogs |
Position equinox : J2000.0 , epoch : J2000.0 |
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Right ascension | 12 h 43 m 57.7 s |
declination | + 32 ° 10 ′ 05 ″ |
Appearance | |
Morphological type | SB (s) m / pec / HII |
Brightness (visual) | 10.1 mag |
Brightness (B-band) | 10.7 mag |
Angular expansion | 15.3 ′ × 2.4 ′ |
Position angle | 33 ° |
Surface brightness | 13.9 mag / arcmin² |
Physical data | |
Affiliation | NGC-4631 group (LGG 291) |
Redshift | 0.002155 ± 0.000003 |
Radial velocity | 646 ± 1 km / s |
Stroke distance v rad / H 0 |
(30 ± 2) x 10 6 ly (9.12 ± 0.64) Mpc |
history | |
discovery | Wilhelm Herschel |
Discovery date | March 20, 1787 |
Catalog names | |
NGC 4656 • NGC 4657 • UGC 7907 • PGC 42863 • CGCG 159-065 • MCG + 05-30-66 • IRAS 12417 + 3228 • KUG 1241 + 324 • 2MASX J1243582 + 321010 • GC 3189 • GC 3190 • H I-176 • H I-177 • h 1414 • h 1415 • KCPG 350B • FGC 174A |
NGC 4656/57 is a barred spiral galaxy of Hubble type SB (s) m in the constellation Canes Venatici the northern sky , the estimated 30 million light-years from the Milky Way 's center.
The appearance of the galaxy is reminiscent of the Small Magellanic Cloud . Because of its characteristic shape, the galaxy is sometimes jokingly called a hockey stick . In the past, the galaxy evidently had a strong interaction with the large neighboring galaxy NGC 4631, a little further to the southeast . One of the effects of this is likely to be a bright, somewhat remote appearing node at the northeastern end of the galaxy. This bright knot was cataloged as a separate object when Wilhelm Herschel discovered the galaxy on March 20, 1787 , which meant that it was later listed in the New General Catalog under a separate entry as NGC 4657 .
Image of a section of the galaxy through the Hubble Space Telescope
SDSS recording