Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

November 17, 1998
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NGC 7635: The Bubble Nebula
Credit & Copyright: T. Bonev et al. (Astron. Inst., U. Bonn), Pik Terskol Obs.

Explanation: What created this huge space bubble? A massive star that is not only bright and blue, but also emitting a fast stellar wind of ionized gas. The Bubble Nebula is actually the smallest of three bubbles surrounding massive star BD+602522, and part of gigantic bubble network S162 created with the help of other massive stars. As fast moving gas expands off BD+602522, it pushes surrounding sparse gas into a shell. The energetic starlight then ionizes the shell, causing it to glow. The Bubble Nebula, also known as NGC 7635, is about 10 light-years across and visible with a small telescope towards the constellation of Cassiopeia.

Tomorrow's picture: Hubble Close-Up of the Bubble Nebula

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