A planetary nebula is a shell of gas produced by a star as it nears the end of its life cycle. Their name can be a bit misleading. They actually have nothing to do with planets. These nebulae were given this name because they often look like planets due to their round shape. The outer shell of gas is usually illuminated by the remains of the star at its center.
1. Helix Nebula ByESO/VISTA/J. Emerson
2. Dumbbell Nebula By Bill Snyder (Bill Snyder Photography)
3. NGC 2818 By Hubble Heritage
4. NGC 6326 By ESA/Hubble and NASA
5. Red Spider Nebula By NASA/STScI/ESA
6. Little Ghost Nebula By Hubble Heritage Team, NASA