NGC 1931
| 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 |
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]
History
[edit]The German-born English astronomer William Herschel discovered the small reflection nebula in 1793 and noted seeing a few stars in the middle.[5] 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]
References
[edit]- ^ a b c "NGC 1931". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2008-11-16.
- ^ Ambartsumian, V. A. (1954-01-01). "Multiple Systems of Trapezium type". Communications of the Byurakan Astrophysical Observatory. 15: 3–40.
- ^ a b Lim, Beomdu; Sung, Hwankyung; Bessell, Michael S.; Kim, Jinyoung S.; Hur, Hyeonoh; Park, Byeong-Gon (2015-04-01). "The Sejong Open Cluster Survey (SOS). IV. the Young Open Clusters NGC 1624 and NGC 1931". The Astronomical Journal. 149: 127. doi:10.1088/0004-6256/149/4/127. ISSN 0004-6256.
- ^ a b Dewangan, L. K.; Ojha, D. K.; Zinchenko, I.; Janardhan, P.; Luna, A. (2017-01-01). "Multiwavelength Study of the Star Formation in the S237 H II Region". The Astrophysical Journal. 834: 22. doi:10.3847/1538-4357/834/1/22. ISSN 0004-637X.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Herschel, William (1802). "Catalogue of 500 New Nebulae, Nebulous Stars, Planetary Nebulae, and Clusters of Stars; With Remarks on the Construction of the Heavens". Philosophical Transactions of the Royal Society of London. 92: 477–528. ISSN 0261-0523.
- ^ Collinder, Per (1931-01-01). "On Structural Properties of Open Galactic Clusters and their Spatial Distribution. Catalog of Open Galactic Clusters". Annals of the Observatory of Lund. 2: B1 – B46.
- ^ Sharpless, Stewart (1959-12-01). "A Catalogue of H II Regions". The Astrophysical Journal Supplement Series. 4: 257. doi:10.1086/190049. ISSN 0067-0049.
External links
[edit]
- NGC 1931 @ Wikisky
- NGC 1931 @ SEDS NGC objects pages
- Sharpless 237 Archived 2011-09-30 at the Wayback Machine
