from Wikipeda: The complex has the following
New General Catalogue (NGC) designations:
- NGC 2237 – Part of the nebulous region (Also used to denote whole nebula)
- NGC 2238 – Part of the nebulous region
- NGC 2239 – Part of the nebulous region (Discovered by John Herschel)
- NGC 2244 – The open cluster within the nebula (Discovered by John Flamsteed in 1690)[citation needed]
- NGC 2246 – Part of the nebulous region
The cluster and nebula lie at a distance of 5,000
light-years from
Earth[3] 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.
[4][5] Most of the ongoing star-formation activity is occurring in the dense molecular cloud to the south east of the bubble.
[6]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.
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