What happens to stars around the size of the sun?
STAGE 1: Main Sequence
A star's life begins when nuclear reactions start deep in the core. Hydrogen nuclei are fused to form a helium nucleus. Each helium nucleus has slightly less mass than the hydrogen nuclei that formed it. The missing mass is converted into energy. This energy released in the core creates high temperatures and pressures. The high internal pressure would blow the star apart if not for the weight of the outer layers pressing down upon the core.
The star spends almost all of its life on the main sequence as a very average star.