1. Main Sequence: For billions of years, the star fuses hydrogen into helium in its core, generating energy and maintaining its stability. This is the "main sequence" stage.
2. Red Giant: When the hydrogen fuel runs out, the core contracts and heats up. This causes the outer layers to expand and cool, transforming the star into a red giant.
3. Helium Burning: The core gets hot enough to fuse helium into heavier elements like carbon and oxygen. This phase is relatively short.
4. Planetary Nebula: Eventually, the star's outer layers are expelled into space, creating a beautiful, colorful cloud called a planetary nebula.
5. White Dwarf: The remaining core, now mostly carbon and oxygen, is incredibly dense and hot. It is called a white dwarf. It continues to cool down slowly over trillions of years, eventually becoming a black dwarf, which is a cold, dark remnant.
Key points to remember:
* White dwarfs are incredibly dense. They are about the size of Earth but have a mass similar to the Sun.
* They are very hot but slowly cool down over time.
* White dwarfs are the final stage for stars like our Sun.
Let me know if you have any other questions!
