The Rosette Nebula is a large emission nebula located in the constellation
of Monoceros. The brighter portions of the Rosette have been assigned
collectively known as NGC 2244, are super-hot O-type stars which provide
the ultraviolet radiation which causes the gas of the nebula to glow.
It is believed that the radiation pressure from the stars of NGC 2244,
which formed from the nebula, is the cause of the central hole.
Astronomers also believe that the central stars formed less than
1 million years ago and that the intense stellar wind from these stars
is presently dissipating the nebula.

The Rosette Nebula is believed to be 5,500 light years distant with
an estimated diameter of 130 light years.