Messier 57 is a planetary nebula located in Lyra. A planetary nebula when a star nears the end of its life at the end of its red giant phase, the outer layers are blown off as the star shrinks down to be come a white dwarf. The exposed core of the star ionizes the surrounding gas causing it to glow. Planetary nebula typically only last a few ten thousands of years as the gas dissipates.
The blueish-green light comes from ionized oxygen, and the red outer layers come from ionized hydrogen. In deeper images it can be seen extending out much further. The central star shines at magnitude 14.8