The Rosette Nebula (also known as
Caldwell 49) is an H II region located near one end of a giant
molecular cloud in the Monoceros region of the Milky Way
Galaxy. The open cluster NGC 2244 (Caldwell 50) is closely
associated with the nebulosity, the stars of the cluster
having been formed from the nebula's matter.
The
cluster and nebula lie at a distance of 5,000 light-years from
Earth and measure roughly 130 light years in diameter. The
radiation from the young stars excites the atoms in the
nebula, causing them to emit radiation themselves producing
the emission nebula we see. The mass of the nebula is
estimated to be around 10,000 solar masses.
A survey
of the nebula with the Chandra X-ray Observatory has revealed
the presence of numerous new-born stars inside optical Rosette
Nebula and studded within a dense molecular cloud. Altogether,
approximately 2500 young stars lie in this star-forming
complex, including the massive O-type stars HD 46223 and HD
46150, which are primarily responsible for blowing the ionized
bubble. Most of the ongoing star-formation activity is
occurring in the dense molecular cloud to the south east of
the bubble |