Science

The word and phrase "planet" and "planetary nebula" derive from the same root as "plane" and "plan". It would be a misnomer if "planetary nebula" derived from "planet", but it does not.

Planets travel quite close to a single plane around each star, including this solar system. Planetary nebula as we see them are basically rings, hence close to a single plane. But the nebula does not orbit, at least not the same way planets do. And they are larger than planet orbits.

The writers of these pieces frequently find themselves explaining the difference between them. It must be a relatively common misconception (easy enough) running around out there, or perhaps there are a lot of incidental low info readers of such articles.