Proton-proton chain

A proton-proton chain is the fusion reaction of four protons which become a helium atom with two protons and two neutrons, and a very energetic light wave, a photon. A neutrino is also produced in this chain.

The process is efficient at temperatures above 10,000,000° K. In most less massive stars, this chain is the primary source of heat and radiation. The proton-proton chain converts hydrogen into helium releasing energy in the form of particles and gamma-rays. Hydrogen is converted into helium in a chain of reactions. The first reaction takes an average of 1 billion years to occur while the others are much shorter. Generally there are so many hydrogen nuclei that the 1 billion year waiting period does not stop it from producing tremendous radiation.