Bubble Nebula (NGC 7635)

The Bubble Nebula, designated as NGC 7635 (aka Sharpless 162, or Caldwell 11) is one of the most exquisite wonders of our galaxy.

It was discovered in 1787 by William Herschel.

The "bubble" is created by the stellar wind from a massive hot, 8.7 magnitude young central star, the 15 ± 5 M☉ SAO 20575 (BD+60 2522). The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. The star SAO 20575 or BD+602522 is thought to have a mass of 10-40 Solar masses. (via Wikipedia)