What Can Be Seen Within Planetary Nebulae ?

Abstract

A planetary nebula is formed at the end of the life of a star which has a mass about equal to that of our Sun. Any much more massive star cannot pass through this relatively gentle stage; it explodes in a shattering supernova. A star much less massive than the Sun simply fades out slowly, like an ember from a campfire. As you look out into the Milky Way, over half of the stars you see will pass through this planetary nebula phase as their final curtain call.