What’s behind this interstellar phenomenon floating in the far reaches of space?
11,000 light years away in the Cassiopeia constellation can be found this fascinating nebula that at first glance bears resemblance to a bubble. Also known as NGC 7635, the ten-light-year-wide Bubble Nebula is an emission nebula that was formed from a young and hot star at its centre.
It was first discovered in 1787 by William Herschel, and since then it has been the subject of detailed observations. Near the centre of the bubble can be seen the bright star BD+60°2522, several hundred thousand times more luminous and nearly 50 times more massive than the Sun. This star blasted out intense radiation and a fierce stellar wind, which in turn interacted with denser material in a surrounding molecular cloud and formed the Bubble Nebula. «
The nebula itself is one of three shells of gas originating from BD+60°2522. This star also ionises the shell by continuously emitting energetic radiation, which causes it to shine. Aside from the interesting shells that glow from the interaction with its central star, some wisps near the bottom right of the image are the remnants of a supernova explosion thousands of years old.