What Happens inside our Sun ?

Proton-Proton Fusion
- Proton-proton fusion is the nuclear fusion process that fuels the sun and other stars that have core temperature of < 15 million Kelvin
- This reaction cycle yields about 25MeV of energy
- Overview:
- Step 1: Two protons are fused together - this requires very high temperature
- Step 2: one of the proton is transmuted into a neutron under influence of the Weak force forming a deuterium ("heavy hydrogen")
  
  This process forms one neutrino and one positron. The neutrino escapes the sun very quickly (2 sec). The positron will combine with an electron.
- Step 3: The deuterium combines with one proton into a Helium-3 nucleus
- Step 4: Two Helium-3 nuclei are fused together:
- Step 5: The fused Helium-3 nuclei split of two protons and one alpha-particle (a Helium-4 nucleus, which is very stable):