Here's why:
* Red Giant Phase: Red giants are stars in a late stage of evolution. They've exhausted the hydrogen fuel in their core and are fusing heavier elements like helium. This process causes the star to expand significantly.
* Outer Layer Loss: The outer layers of the red giant are loosely bound and easily blown away by stellar winds.
* Core Collapse: As the outer layers are expelled, the core, primarily composed of carbon and oxygen, contracts under its own gravity. This contraction leads to a significant increase in temperature and density.
* White Dwarf Formation: The core stabilizes as a white dwarf. It is extremely dense, with a mass comparable to the Sun but a size similar to Earth. White dwarfs are supported against further collapse by electron degeneracy pressure, a quantum mechanical effect that prevents electrons from occupying the same energy state.
White dwarfs are the final stage for stars like our Sun. They slowly cool down and eventually fade into faint, cold remnants.
