How do planetary nebulae form around dying Sun-like stars?

Planetary nebulae form during the final stages of the evolution of low-mass stars, such as the Sun. As these stars exhaust their nuclear fuel, they evolve into red giants, characterized by large, cool, and unstable outer envelopes.123

The formation process involves the following key stages:

• Mass Loss: Before the nebula is ejected, the red giant experiences significant mass loss through a slow-moving stellar wind, often obscured by dust.4
• Ejection: Triggered by instabilities in the helium-burning shell and the outward force of radiation, the star catastrophically sheds its extended, hydrogen-rich outer layers.32
• Ionization: The loss of this atmosphere exposes the star's hot, dense core. This core emits intense ultraviolet radiation, which ionizes the previously ejected gas, causing it to glow as a planetary nebula.425
• Final State: The remaining core, now a hot and luminous object, eventually cools and shrinks to become a white dwarf star, while the surrounding nebula gradually expands, dilutes, and dissipates into the interstellar medium.245