About image
This image shows a rich area in the constellation Cassiopeia, towards the border with the constellation of Cepheus.
The open cluster visible on the left is M 52, composed of a hundred white stars, from which the relatively young age of the cluster can be understood; its estimated distance is 4500 light years.
At the top right is the nebular complex of NGC 7635, also called "Bubble Nebula" because of its shape.
It is an HII region, at whose southern vertex there is an empty structure, caused by the pressure of the radiation of a central blue star, whose stellar wind reaches 2000 km / s; it is a blue giant, which is also responsible for the ionization of the nebula, which then emits its own light. Its distance from the Sun is estimated at 11,000 light years.