The Bubble Nebula, Ngc 7635. Post-it Notes

The Bubble Nebula, NGC 7635. The seething star forming this nebula is 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 over 4 million miles per hour. This outflow sweeps up the cold, interstellar gas in front of it, forming the outer edge of the bubble. As the surface of the bubble's shell expands outward, it slams into dense regions of cold gas on one side of the bubble. This asymmetry makes the star appear dramatically off-center from the bubble, with its location in the 10 o'clock position. Dense pillars of cool hydrogen gas laced with dust appear at the upper left.