Astronomy Picture of the Day

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

December 12, 1995
See Explanation. Clicking on the picture will download the highest resolution version available.
Shapley 1: An Annular Planetary Nebula
Credit: Anglo-Australian Telescope photograph by David Malin
Copyright: Anglo-Australian Telescope Board

Explanation: This strange structure is what can result when a normal star runs out of nuclear fuel in its core. At that time, 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, designated Shapley 1 after the famous astronomer Harlow Shapley, has a very apparent annular ring like structure. Although some of these nebula appear like planets on the sky (hence their name), they actually surround stars far outside our solar system.

Tomorrow's picture: A Delta Rocket Launches

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Authors & editors: Robert Nemiroff (GMU) & Jerry Bonnell (USRA).
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