Why is the term planetary nebula a misleading way to describe the ring of expanding gas thrown out by a red giant during its transformation into a white dwarf?

Answer 1

The term "planetary nebula" is misleading because it suggests a connection to planets, while these nebulae are actually formed from the outer layers of a dying star, specifically a red giant. The name originated from their round, planet-like appearance in early telescopic observations, but they have nothing to do with planets themselves. Instead, planetary nebulae are the remnants of stellar evolution, showcasing gas and dust expelled by stars, often leading to the formation of new stars. Thus, the terminology inaccurately conveys the true nature of these celestial phenomena.