NGC 7635

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.
The Nebula is 7 light-years across – about one-and-a-half times the distance from our sun to its nearest stellar neighbour, Alpha Centauri – and resides 7,100 light-years from Earth.