What are the main elements that make up a star?

Answer 1

For main sequence stars, the vast majority is hydrogen and helium. Older stars will exhaust these lighter elements near their cores and begin fusing heavier elements.

Answer 2

Stars are primarily composed of hydrogen and helium, with smaller amounts of heavier elements. They generate energy through nuclear fusion in their cores, where high temperatures and pressures cause hydrogen atoms to fuse into helium, releasing energy in the process. Stars also have a structure that includes layers like the core, radiative zone, convective zone, and outer atmosphere.