What Are Stars?

Stars, like humans, have a lifecycle: they are born, age, and die. Formed from dust and gas, stars are categorized into three main types based on age and size. Most stars, including the Sun, are main sequence stars, stable and fueled by nuclear fusion. As they age, they become giants, expanding as they exhaust hydrogen and start using helium. Depending on their size, giants may become planetary nebulae or white dwarfs. Supergiants explode as supernovae, potentially forming neutron stars or black holes. The elements released in these explosions contribute to the formation of new stars and planets.

What are the three main types of stars based on age and size?

Describe the process that occurs when stars age and become giants.

What happens to red giants as their outer layers expand?

Explain the fate of super giant stars after they explode as supernovae.

How do the elements created by dying stars contribute to the formation of new stars and planets?