What is the final stage of a low to average star's life cycle?

The final stage of a low to average star's life cycle is that it becomes a white dwarf. After going through its red giant phase, during which the outer layers of the star are expelled, what remains is the core. This core is extremely hot and dense, consisting primarily of carbon and oxygen but no longer undergoing nuclear fusion. As the star cools down over billions of years, it fades away, leaving the white dwarf as a remnant.

This phase is significant because white dwarfs are what remain after the star has exhausted its nuclear fuel and no longer supports fusion reactions. They will eventually cool down and become what is known as black dwarfs, although this stage has not been observed yet since the universe is not old enough for any white dwarfs to have cooled to that point.

Understanding this process helps clarify the lifecycle of stars based on their mass and progenitors, giving insights into the evolution of galaxies and the recycling of stellar materials into new stars and planetary systems.