Here's why:

* Sun's mass: The Sun is a relatively small star, about 0.8 solar masses.

* Stellar evolution: Stars like our Sun follow a specific evolutionary path. They burn hydrogen into helium in their core for billions of years. When the hydrogen fuel runs out, the core contracts and heats up, causing the outer layers to expand and cool, forming a red giant.

* White dwarf formation: After the red giant phase, the Sun will shed its outer layers, leaving behind a dense, hot core called a white dwarf. This core is composed primarily of carbon and oxygen, the remnants of the fusion processes that powered the Sun.

White dwarfs are incredibly dense, packing the mass of our Sun into a sphere about the size of Earth. They slowly cool down over billions of years, eventually becoming cold, dark objects called black dwarfs. However, the universe is not old enough for black dwarfs to have formed yet.