2011 August 16
Explanation: What happens when a star runs out of nuclear fuel? For stars about the mass of our Sun, the centre 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 nebulae appear like planets on the sky (hence their name), they actually surround stars far outside our Solar System.
Authors & editors:
Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
A service of: ASD at NASA / GSFC
& Michigan Tech. U.