The energy source for all main sequence stars is nuclear fusion of hydrogen into helium. This process is called hydrogen burning.
During hydrogen burning, four hydrogen nuclei (protons) combine to form one helium nucleus. This reaction releases a large amount of energy in the form of light and heat, which provides the energy for the star to shine.A star begins its life as a protostar, a clump of gas and dust that collapses under its own gravity.
As the protostar collapses, its core becomes hot and dense enough to ignite hydrogen burning, which marks the start of its main sequence phase. The main sequence phase is when a star spends most of its life, fusing hydrogen into helium and releasing energy in the process.
To know more about hydrogen visit:-
https://brainly.com/question/30623765
#SPJ11