What is the primary element consumed by main-sequence stars in fusion?

Main-sequence stars primarily fuse hydrogen into helium in their cores. This process, known as hydrogen burning, occurs through nuclear fusion where hydrogen nuclei (protons) combine under extreme temperatures and pressures. The energy released during this fusion process is what powers the star and provides the heat and light that we observe.

Hydrogen is the most abundant element in the universe, making it the primary fuel for the nuclear reactions that sustain stars during the main sequence phase of their life cycle. As stars evolve, they may begin to fuse heavier elements, but during the main-sequence stage, hydrogen remains the dominant element involved in these fusion processes. This is crucial for understanding stellar evolution, as the duration of the main sequence phase and the eventual transition to later stages of stellar development depend largely on the available hydrogen fuel.

Other elements mentioned, such as helium, oxygen, and carbon, play roles in later stages of stellar evolution once a star has exhausted its hydrogen supply and begins fusing heavier elements, but they are not the primary elements consumed during the main sequence phase.