| NGC 1581 | |
|---|---|
 NGC 1581 theHubble Space Telescope | |
| Observation data (J2000epoch) | |
| Constellation | Dorado |
| Right ascension | 04h 24m 44.9s[1] |
| Declination | −54° 56′ 31″[1] |
| Redshift | 0.005337 ± 0.000090[1] |
| Heliocentric radial velocity | 1,600 ± 27 km/s[1] |
| Distance | 67.8 ± 4.9Mly (20.8 ± 1.5Mpc)[1] |
| Group orcluster | Dorado Group |
| Apparent magnitude (V) | 12.5[2] |
| Characteristics | |
| Type | S0-[1] |
| Apparent size (V) | 1.8′ × 0.7′[1] |
| Other designations | |
| ESO 157-26, IRAS04236-5503,PGC 15055 | |
NGC 1581 is alenticular galaxy in the constellationDorado. The galaxy lies about 65 millionlight years away from Earth, which means, given its apparent dimensions, that NGC 1581 is approximately 40,000 light years across.[1] It was discovered byJohn Herschel on December 5, 1834.[3] It is a member of theDorado Group.[4] NGC 1581 forms a pair with spiral galaxyNGC 1566, which lies at a distance of 41 arcminutes, which corresponds to a projected distance of 210,000 parsecs (680,000 ly).[5]
NGC 1581 features an inner ring visible inH-alpha and [N II] images. The ring is brighter towards its western part. There are brightH II regions near the centre and the inner ring of the galaxy. It is possible the star formation in the ring of the galaxy is fueled by gas NGC 1581 stripped from the larger NGC 1566. However, currently, the galaxy doesn't show obvious signs of interaction.[6] A diffuse hydrogen trail is indicative of the past interaction of the two galaxies.[7] A low surface brightness galaxy, LSB-D, lies about at the same projected distance from NGC 1581 and NGC 1566, about 190 kpc. Between LSB-D and NGC 1581 has been detected a hydrogen cloud.[7]
