NGC 7635 - Bubble nebula

The Bubble Nebula in SHO

NGC 7635 (The Bubble Nebula)
GT102 f/5.5 APO with ASI1600mm Pro Camera
7.5 hrs total integration time

NGC 7635, also known as the Bubble Nebula, Sharpless 162, or Caldwell 11, is an H II region emission nebula in the constellation Cassiopeia. It lies close to the direction of the open cluster Messier 52. The "bubble" is created by the stellar wind from a massive hot, 8.7 magnitude young central star, SAO 20575. (Wikipedia)

The Bubble Nebula is 7 light-years across and lies at a distance of 7,100 light-years from Earth. The star forming this nebula is about 45 times more massive than our sun. Gas on the star gets so hot that it escapes away into space as a "stellar wind" moving at an incredible 4 million miles per hour. This outflow sweeps up the cold, interstellar gas in front of it, forming the outer edge of the bubble. (Hubblesite)

Taken with my 102mm APO refractor and ASI1600mm camera, this is a narrowband image processed in the Hubble palette (SHO). Additional details on the image capture can be found at Bubble Nebula