What is "planetary nebulae"

Usage examples of "planetary nebulae".

It appears to remain stable in size, rather than expanding as do planetary nebulae.

In both the near and far distances around this little solar system, like the walls of a beautiful room, there were dust mists, shining gases, clusters, and at least two noticeable planetary nebulae in ring form, still expanding, their cores in nuclear burn, on the long path to becoming white dwarfs.

The Universe was littered with planetary nebulae, supernovae ejecta and the other debris of dying stars, all rich with complex&mdash.

The Universe was littered with planetary nebulae, supernovae ejecta and the other debris of dying stars, all rich with complex—.