Hi there! I will be explaining the life cycle of a star. Let's go on a trip to our solar system.
Stars start out as a main sequence. Its composition is > 98% hydrogen and helium. 1/3 of the hydrogen is converted to helium.
As hydrogen expands in their cores, these stars extend their outer layers and can grow over 100 times their main sequence size. In this stage, the star is called a red giant.
Next, the outer layers of gas are ejected while the star's core contracts into a white dwarf. This is called a planetary nebula.
The next stage of a star is the white dwarf. This star core is usually made of carbon and oxygen. It can also have neon, magnesium and helium.
Lastly and hypothetically, a star turns into a black dwarf. The Universe's existence is too short to determine its existence but there is a possibility that it exists. Thank you for coming on this journey with me to learn about stars. I hope you enjoyed!