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.

2011 August 16
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Shapley 1: An Annular Planetary Nebula
Image Credit: ESO

Explanation: What happens when a star runs out of nuclear fuel? For stars about the mass of our Sun, the center condenses into a white dwarf while the outer atmospheric layers are expelled into space and appear as a planetary nebula. This particular planetary nebula, pictured above and designated Shapley 1 after the famous astronomer Harlow Shapley, has a very apparent annular ring like structure. Although some of these nebulas appear like planets on the sky (hence their name), they actually surround stars far outside our Solar System.

Tomorrow's picture: open space

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