Rosette nebula (NGC 2237), optical image. - HD Stock-Video

This nebula is an emission nebula, known as the Rosette nebula because of its round, flower-like shape. Emission nebulae are clouds of gas and dust that are ionised by radiation from hot stars within them, causing them to glow. At the heart of the nebula (centre) is the cluster of young stars (NGC 2244) responsible for this ionisation. The strong stellar wind from these stars has cleared a hole around them. The whole Rosette nebula measures around 50 light years across; it lies approximately 4500 light years away in the constellation Monoceros