NGC 251
Galaxy in the constellation Pisces
From Wikipedia, the free encyclopedia
NGC 251 is a spiral galaxy in the constellation of Pisces. Its velocity with respect to the cosmic microwave background for is 4,224±23 km/s, which corresponds to a Hubble distance of 203.2 ± 14.3 Mly (62.30 ± 4.37 Mpc).[2] Additionally, six non redshift measurements give a distance of 205.32 ± 5.54 Mly (62.950 ± 1.699 Mpc).[4] It was discovered on October 15, 1784, by German-British astronomer William Herschel.[5]
Right ascension00h 47m 54.0517s[1]
Declination+19° 35′ 48.788″[1]
| NGC 251 | |
|---|---|
SDSS image of NGC 251 | |
| Observation data (J2000 epoch) | |
| Constellation | Pisces |
| Right ascension | 00h 47m 54.0517s[1] |
| Declination | +19° 35′ 48.788″[1] |
| Redshift | 0.015184[2] |
| Heliocentric radial velocity | 4556 km/s[2] |
| Distance | 204.36 ± 12.64 Mly (62.657 ± 3.876 Mpc)[2] |
| Apparent magnitude (B) | 14.6[3] |
| Characteristics | |
| Type | Sc[2] |
| Size | 149,300 ly (45,780 pc)[2][note 1] |
| Apparent size (V) | 2.4′ × 1.9′[2] |
| Other designations | |
| KPG 015B, UGC 490, PGC 2806, CGCG 458-005[3] | |
According to I.D. Karachentsev, NGC 251 forms an isolated galaxy pair with UGC 477.[6]
One supernova has been observed in NGC 251: SN 2023rky (type II, mag. 18.6) was discovered by the Zwicky Transient Facility on 6 September 2023.[7]
Notes
- POSS1 103a-O values used.
