main sequence

The main sequence is a phase in a star's life where it spends most of its existence, including our Sun. During this stage, stars fuse hydrogen into helium in their cores, generating energy that produces light and heat. This process keeps them stable and defines their size and brightness. The main sequence is represented on the Hertzsprung-Russell diagram, a chart that categorizes stars by their temperature and luminosity. Stars remain in this phase for millions to billions of years, depending on their mass, before evolving into different stages, such as red giants or supernovae.