The Bubble Nebula, NGC 7635, was discovered in 1787 by William Herschel and is shown here in a Hubble Space Telescope WFC3 image. The outer edge of the bubble – 7 light years across – comprises cold interstellar gas displaced by winds from a 45-solar-mass young O star (BD +60°2522), seen off-centre at 10 o’clock. Dense pillars of cool hydrogen gas appear above and behind the bubble. Blue colours indicate oxygen, green is hydrogen, and red is nitrogen. (NASA, ESA and the Hubble Heritage Team [STScI/AURA])
This image is published in the June 2016 issue of Astronomy & Geophysics.