The Rosette Nebula and NGC 2244 cluster
The Rosette Nebula exhibits a striking circular symmetry which gives it the appearance of a partly opened rose, an allusion further enhanced by the rich red hues seen in this colour photograph. Near the centre of the nebula is a cluster of blue stars catalogued as NGC 2244. These stars are responsible for making the nebula visible and for creating the hollowed-out central cavity. This cluster of stars formed from the gas which now surrounds it less than a million years ago and is thus very young on the cosmic timescale. The gas and dust at the centre of the nebula have been forced away from the bright stars by radiation pressure and the intense stellar wind which is often associated with very hot stars, forming a hollow centred on the cluster. This will gradually expand and dissipate until the stars are free from nebulosity. 
AAO image reference UKS 9.
© Anglo-Australian Observatory/Royal Observatory, Edinburgh
Photograph from UK Schmidt plates by David Malin, text © David Malin.
For details of object position and photographic exposure, search technical table by UKS reference number.

Related images
AAT 35 The Rosette nebula and NGC 2244 cluster