The Bubble Nebula, NGC 7635 (SH162/Caldwell 11)

This 10 year diameter bubble is being blown out of the surrounding molecular cloud by the massive star SAO 20575 (BD+60 2522).

This is what's known as a Wolf-Rayet star, a young, massive and extremely hot star that's burning its fuel rapidly and is approaching the supernova stage.

It's thought to be between 10 and 40 times as massive as the sun. It's the bright star in the bubble, but isn't at the centre of the bubble due to the different densities of the surrounding material.
The bubble is being produced by the solar wind from the star, estimated to be at a speed of 4 million kph. The UV radiation from the star is ionizing the gas causing it to glow at a temperature of about 10,000K, which, when you consider the size of the region, gives some idea of the tremendous energies involved.

A second, larger bubble can be seen in this image, the edge of which is next to the bright blue star in the lower right.
The nebula is 11,300 light years away near the constellation of Cassiopeia and was discovered in 1787 by Sir William Herschel.

Click on image below for full size version



Telescope. 12 inch custom Ritchey Chretien @ F5.3

Camera. Atik 460EX using Baader filters

H-Alpha. 32 x 10 minutes

OIII. 18 X 10 minutes

RGB, all 3 minutes each, 12 red, 12 green & 25 blue.

Imaged in January and February 2013 from Dorset, England.












Meade LX200GPS 14" @ F6.3
Atik 16 HR
Astronomik 13nm narrowband filters

30 x 6 minute Ha
10 x 6 minute OIII & H-beta
Total imaging time. 5 hours.

Imaged on 30thAugust 2008.