Rosette Nebula

Rosette Nebula

The Rosette Nebula (also known as Caldwell 49 or NGC 2237) is a large emission nebula located in the constellation Monoceros, approximately 5,200 light-years from Earth. It spans about 130 light-years in diameter, making it one of the largest known star-forming regions. The nebula has an apparent size of 1.3 degrees, roughly 2.5 times the diameter of the full Moon.

It is closely associated with the young open star cluster NGC 2244 (Caldwell 50), whose hot, massive O-type stars (HD 46223 and HD 46150) ionize the surrounding hydrogen gas, causing the nebula to glow in red hues. These stars formed from the nebula’s material within the last 5 million years and are responsible for carving a central cavity through intense stellar winds and radiation.

The Rosette Nebula contains an estimated 10,000 solar masses of gas and dust and hosts around 2,500 young stars, making it a highly active stellar nursery.