Respuesta :

When the red giant star starts to die out, throwing out the last outer layers. It forms a glowing ring of gas called the planetary nebula.
PBCHEM

Answer : Planetary Nebula.

Explanation : A planetary nebula is formed when a red giant star throes off abut half of its mass and disintegrates.

Planetary Nebula is abbreviated as PN or plural PNe, is observed to be a type of emission nebula consists of expanding, glowing shell of ionized gas which is ejected from red giant stars late in their lives.