When the outer envelope of a red giant is ejected?

When the outer envelope of a red giant is ejected, it marks the end of its life cycle as the star sheds its outer layers. This event typically occurs during the asymptotic giant branch (AGB) phase, leading to the formation of a planetary nebula. The core that remains becomes a white dwarf, which will eventually cool and fade over time. The ejected material enriches the surrounding interstellar medium with heavier elements, contributing to the formation of new stars and planets.