The Rosette Nebula

The Rosette Nebula is one of the most captivating objects in the night sky. It’s frequently cited, incorrectly, as NGC 2244. That designation, as well as Caldwell 50, refers to the open star cluster, called the Satellite Cluster, at its center. NGC 2237 refers to the nebula itself, as do Sh2-275 and Caldwell 49. An open star cluster is a group of stars likely born in the same stellar nursery, but not bound gravitationally and destined to find their own paths through the galaxy. It’s also catalogued as Caldwell 50 (C50).

NGC 2244 is a very young star cluster with an age between one and five million years, but it’s very active, providing the radiation that allows us to see NGC 2237, the Rosette Nebula, by ionizing its gasses.

The pair are about 4,500 light years from Earth and the Rosette Nebula is huge—50 light years across. The Rosette Nebula glows with light emitted from ionized sulfur (red), hydrogen (green), and oxygen (blue). These gasses mix to form the expansive palette of colors you see in the image.

The Rosette Nebula is a prime example of a Strömgren sphere. A Strömgren sphere is a bubble of ionized hydrogen surrounding a massive hot star.

The Rosette contains a number of dark, dusty globules that would normally be prime locations for the formation of new stars. But the intense radiation from the nearby star cluster is eating away at them, likely preventing them from doing this.