Messier Object 57 - definition of Messier Object 57 by The Free Dictionary
Ring Nebula (redirected from Messier Object 57)
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Ring Nebula (rĭng)
A planetary nebula in the constellation Lyra.
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Also known as Messier Object 57
and NGC 6720, it is one of the best examples of a planetary nebula, a shell of material ejected from a dying star.