NGC 2237 The Rosette Nebula
37 x 600 seconds with Astrodon Ha & OIII filters.
The Rosette Nebula is a large, circular emission nebula in the constellation Monoceros. It surrounds a cluster of hot, young stars known as the Rosette Cluster (NGC 2244)
The Rosetta Nebula is a vast cloud of dust and gas extending over 1° across, and covers an area about 5 times that of the full moon.
The Rosette is an H II region at a distance of some 5,200 light years, near one end of a large molecular cloud in Monoceros (though distance estimates vary considerably). Its diameter is about 130 light years, and the central hole is about 30 light years across. The nebula is estimated to contain around 10,000 solar masses.
The open cluster NGC 2244 is closely associated with the nebulosity, having recently formed from the nebula itself. Ultraviolet radiation from its hot O-type stars energizes the nebula, causing it to fluoresce. They heat the surrounding gas to a temperature around 6 million K, generating large amounts of X-ray emission seen by the Chandra X-ray Observatory in 2001.
Stellar winds from this group of stars have swept out the hollow at the center of the Rosette. These stellar winds exert pressure on the interstellar cloud, and compress it. This leads to star formation, which is currently still ongoing in this vast cloud of interstellar matter; astronomers announced the finding of a very young star with a Herbig-Haro jet in 2004.