NGC 4644
| Galaxy NGC 4644 |
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|---|---|
![LEDA 42725, NGC 4644 & LEDA 2816018 [1] SDSS mount](https://de.wikipedia.org/wiki/Datei:NGC4644_-_SDSS_DR14.jpg)
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| LEDA 42725, NGC 4644 & LEDA 2816018 SDSS Recording | |
| AladinLite | |
| Constellation | Big Bear |
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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".