* Red Giant Phase: After exhausting the hydrogen fuel in their core, medium-sized stars (like our Sun) expand into red giants. This expansion is due to the fusion of hydrogen in a shell surrounding the core, causing the star to swell significantly.
* Helium Burning: The core of the star, now primarily composed of helium, starts to contract and heat up. Eventually, the temperature and pressure become high enough to ignite helium fusion, producing carbon and oxygen.
* Planetary Nebula: After the helium is consumed, the star sheds its outer layers, creating a beautiful cloud of gas and dust known as a planetary nebula.
* White Dwarf: The remaining core, composed of carbon and oxygen, is incredibly dense and hot, forming a white dwarf. White dwarfs are about the size of Earth but contain roughly the same mass as our Sun. They gradually cool and fade over billions of years.
Key Points:
* Only medium-sized stars become white dwarfs. Larger stars go through different evolutionary paths, potentially leading to supernovae and neutron stars or black holes.
* The white dwarf stage is the final stage for stars like our Sun. It is a relatively stable and long-lasting phase.
Let me know if you have any other questions about star evolution!
