Blown by the wind from a massive star, this interstellar apparition has a surprisingly familiar shape. Cataloged as NGC 7635, it is also known simply as The Bubble Nebula. This image includes a long exposure through a hydrogen alpha filter to reveal details of the cosmic bubble and its environment. Although it looks delicate, the 10 light-year diameter bubble offers evidence of violent processes at work. Above and right of the Bubble's center is a hot, O-type star, several 100,000 times more luminous and approximately 45 times more massive than the Sun. A fierce stellar wind and intense radiation from that star has blasted out the structure of glowing gas against denser material in a surrounding molecular cloud. The Bubble Nebula lies a mere 11,000 light-years away toward the constellation Cassiopeia.
This image was taken over the nights of October 9 through the 12th, and totals 11 hours of exposure. 7 hours were taken through a hydrogen alpha filter. Click on the image to see more detail.