NGC 4644
Galaxy NGC 4644 |
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LEDA 42725, NGC 4644 & LEDA 2816018 SDSS Recording | |
AladinLite | |
Constellation | Big Bear |
Position equinox : J2000.0 , epoch : J2000.0 |
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Right ascension | 12 h 42 m 42.657 s |
declination | + 55 ° 08 ′ 43.85 ″ |
Appearance | |
Morphological type | SBb / P |
Brightness (visual) | 13.8 mag |
Brightness (B-band) | 14.6 mag |
Angular expansion | 1.6 ′ × 0.5 ′ |
Position angle | 53 ° |
Surface brightness | 13.4 mag / arcmin² |
Physical data | |
Affiliation | NGC 4686 group LGG 300 |
Redshift | 0.016501 ± 0.000130 |
Radial velocity | 4947 ± 39 km / s |
Stroke distance v rad / H 0 |
(225 ± 16) x 10 6 ly (69.0 ± 4.9) Mpc |
history | |
discovery | Wilhelm Herschel |
Discovery date | April 14, 1789 |
Catalog names | |
NGC 4644 • 4644A • UGC 7887 • PGC 42708 • CGCG 270-014 • MCG + 09-21-030 • GC 3177 • H II 794 • h 1406 • 2MASS J12424266 + 5508440 • LDCE 914 NED001 • WISEA J124242.66 + 550844.2 • HOLM 447A • KPG 352A |
NGC 4644 is a 13.8 mag bright bar-spiral galaxy of the Hubble type SBb / P in the constellation Great Bear in the northern sky . It is an estimated 225 million light years away from the Milky Way and about 115,000 light years in diameter. Together with PGC 42725 ( NGC 4644b ) it forms the gravitationally bound galaxy pair Holm 447 or KPG 352 and is considered a member of the NGC 4686 group ( LGG 300 ).
In the same area of the sky are the galaxies NGC 4646 , NGC 4669 , NGC 4675 .
The object was discovered on April 14, 1789 by Wilhelm Herschel with an 18.7-inch reflector telescope, who described it as "F, S".