NGC 1931
Nebula and open cluster in the constellation Auriga
From Wikipedia, the free encyclopedia
NGC 1931 is a reflection and emission nebula and around a young star cluster in the constellation Auriga. The nebula shares similarities to the Orion Nebula as it is a mixed emission-reflection nebula that also contains a small Trapezium of hot young stars.[2] At around 2 million years of age,[3] most of the ongoing star formation in the star cluster is hidden away in the nebula.[4] It is believed that the main ionizing source for the dusty molecular cloud is a single, hot B-type star.[3] The distance from Earth is estimated at 7500 light years.[4]
| Reflection nebula | |
|---|---|
| emission nebula | |
NGC 1931 | |
| Observation data: J2000.0 epoch | |
| Right ascension | 5h 31m [1] |
| Declination | +34° 15′[1] |
| Distance | ~7500 ly |
| Apparent magnitude (V) | 10.1[1] |
| Apparent dimensions (V) | 7′ |
| Constellation | Auriga |
History
The German-born English astronomer William Herschel discovered the small reflection nebula in 1793 and noted seeing a few stars in the middle.[5] IC 417 is a nearby nebula discovered in 1892. In 1931, Swedish astronomer Per Collinder included it in his catalog of open star clusters as the "nebulous cluster" Collinder 68.[6] American astronomer Stewart Sharpless cataloged the emission component, which lies outside the center, as Sh 2-237 in 1959.[7]
