nucleosynthesis: The Proton-Proton Cycle

In the proton-proton cycle, two hydrogen nuclei (protons) are fused and one of these protons is converted to a neutron by beta decay (see radioactivity) to make a deuterium nucleus (one proton and one neutron). Then a third proton is added to deuterium to form the light isotope of helium, helium-3. When two helium-3 nuclei collide, they form a nucleus of ordinary helium, helium-4 (two protons and two neutrons), and release two protons. In each of these steps considerable energy is also released.

Sections in this article:

• Introduction
• Creation of the Heavier Elements
• The Carbon-Nitrogen-Oxygen Cycle
• The Proton-Proton Cycle
• Transformation of Hydrogen to Helium
• Bibliography

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