Question

The main source of energy in main sequence stars is ________________.

fusion of hydrogen to helium
gravity
the triple alpha process
the chemical reaction between hydrogen and helium

Answer 1

The main source of energy in main sequence stars is nuclear fusion of hydrogen nuclei into helium. This process occurs at extremely high temperatures in the core of the star, where the proton-proton chain reaction is dominant.

Step-by-step explanation:

The main source of energy in main sequence stars is nuclear fusion of hydrogen to helium. In stars like the Sun, the proton-proton chain dominates, where hydrogen nuclei (protons) are fused into helium, releasing a tremendous amount of energy. This process occurs in the star's core, with temperatures reaching upwards of 14 million kelvin, facilitating the fusion reactions.

In larger stars, a different process known as the triple alpha process becomes important. However, for main sequence stars, which make up about 90% of stars in the universe, the primary energy source is the fusion of hydrogen into helium, sustaining their light and heat for the majority of their lifespans.