TeXes Science Practice Test

What happens to stars that do not have sufficient mass to become black holes?

1. They become main sequence stars.

2. They form red giants.

3. They become white dwarfs.

4. They expire as supernovae.

The correct answer is: They become white dwarfs.

Stars that do not have sufficient mass to become black holes typically conclude their life cycle by transitioning into white dwarfs. This occurs after they have undergone extensive nuclear fusion processes. In the later stages of their evolution, stars like our Sun will expand into red giants, during which they burn heavier elements in their cores before shedding their outer layers. What remains after the outer material has been expelled is the dense core, which is not massive enough to undergo further gravitational collapse into a black hole. Instead, this leftover core cools and dims over time, ultimately becoming a white dwarf. White dwarfs are composed primarily of carbon and oxygen and represent the final stage for stars that have masses less than about eight times that of the Sun. This process reflects the natural life cycle of a star based on its initial mass, with the fate of white dwarfs contrasting with the more massive stars that can end their lives as supernovae or black holes.