Messier 27 is often called the Dumbbell Nebula or Apple Core Nebula because of the brighter lobes on each side of it. It is located in the constellation of Vulpecula, at a distance of 1300 light years.
M27 is a planetary nebula which is a bit of a misnomer since it has nothing to do with planets. The first ones discovered looked a bit like planetary systems, but planetary nebula are created when a dieing star casts off its outer layers after a star's red giant phase. The nebula is made to glow from ionizing radiation from the remains of the star core which shrinks down to form a white dwarf.
Messier 27 was the first planetary nebula cataloged by Charles Messier.