Rosette Nebula / NGC 2237

The Rosetta Nebula (also known by the catalog designations NGC 2237 and C 49) is a large, crudely circular H II region located at the edge of a giant molecular nebula in the constellation Unicornus.

The nebula has an angular diameter of 1.3° and is located at a distance of 1600 parsecs (about 5200 light-years) from the solar system; It has an approximate size of 100 light-years.

At the center of the Rosetta Nebula is a bright open cluster, known as NGC 2244; The blue stars in the cluster, part of the OB association known as Monoceros OB2, emit ultraviolet radiation, which excites the nebula's gas to emit red light. The stellar wind of the O and B group of stars is thought to exert pressure on the interstellar cloud causing compression, followed by star formation; In fact, many Bok globules have been observed in the region, believed to be the site of star formation