The Rosette Nebula (also known as Caldwell 49) is a large, spherical (circular in appearance), H II region located near one end of a giant molecular cloud in the Monoceros region of the Milky Way Galaxy. It is located about 5,000 light years from Earth and measure roughly 50 light years in diameter. The mass of the nebula is estimated to be around 10,000 solar masses.

   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.

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

     Large areas of gas and dust, including giant pillars that remain behind after intense radiation from massive stars has eroded the more diffuse gas.

A diffuse X-ray glow is also seen between the stars in the bubble, which has been attributed to a super-hot plasma with temperatures ranging from 1 to 10 million K.[7] This is significantly hotter than the 10,000 K plasmas seen in HII regions, and is likely attributed to the shock-heated winds from the massive O-type stars.

Technical data of the photo :

Ha 18x600s

R 10x300s, GB 9x300s,  bin1 each

Mount  : AP GTO

Camera  : QSI 683, -20 C

Telescope  : Takahashi FSQ 106