| Emission nebula | |
|---|---|
| H II region | |
 Rosette Nebula in narrowband with Hubble pallette | |
| Observation data:J2000.0epoch | |
| Right ascension | 06h 33m 45s[1] |
| Declination | +04° 59′ 54″[1] |
| Distance | 5,200[2] ly (1,600 pc) |
| Apparent magnitude (V) | 9.0 |
| Apparent dimensions (V) | 1.3° |
| Constellation | Monoceros |
| Physical characteristics | |
| Radius | 65 ly |
| Notable features | Multipart nebula |
| Designations | SH 2-275,[1] CTB 21,[1]Caldwell 49 |
| See also:Lists of nebulae | |
TheRosette Nebula (also known asCaldwell 49) is anH II region located near one end of a giant molecular cloud in theMonoceros region of theMilky Way Galaxy. Theopen clusterNGC 2244 (Caldwell 50) is closely associated with the nebulosity, thestars of the cluster having beenformed from the nebula's matter.
The nebula has been noted to be having a shape reminiscent of a human skull, and is sometimes referred to as the "Skull Nebula". It is not to be confused withNGC 246, which is also nicknamed the "Skull Nebula".[3][4]
The complex has the followingNew General Catalogue (NGC) designations:
The cluster and nebula lie at a distance of 5,000light-years fromEarth[6] and measure roughly 130 light years in diameter. Theradiation from the young stars excites theatoms in the nebula, causing them to emit radiation themselves producing the emission nebula we see. Themass of the nebula is estimated to be around 10,000solar masses.
A survey of the nebula with theChandra 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 thisstar-forming complex, including the massiveO-type stars HD 46223 and HD 46150, which are primarily responsible for blowing the ionized bubble.[7][8]Most of the ongoing star-formation activity is occurring in the dense molecular cloud to the south east of the bubble.[9]
A diffuseX-ray glow is also seen between the stars in thebubble, which has been attributed to a super-hot plasma with temperatures ranging from 1 to 10 million K.[10]This is significantly hotter than the 10,000 K plasmas seen inHII regions, and is likely attributed to the shock-heated winds from the massive O-type stars.
On April 16, 2019, the Oklahoma Legislature passed HB1292 making the Rosette Nebula as the official state astronomical object. Oklahoma GovernorKevin Stitt signed it into law April 22, 2019.[11]
