The Life Cycle of the Stars

The initial fusion process that all stars begin doing is the Proton – Proton chain, or PP chain. Protostars and main sequence stars both utilise the PP chain as their primary power source. The PP chain has three stages.

 

Stage 1:

Four protons (hydrogen nuclei) fuse together to form 2 deuterium nuclei (1 proton, 1 neutron) and emit a pair of positrons and neutrinos as excess. (To conserve charge and energy in the reaction)

 

 

 

Step 2:

The two deuterium nuclei then fuse with another pair of protons in order to form 2 Helium-3 nuclei (2 protons, 1 neutron), gamma rays are also emitted in order to conserve energy.

 

 

 

Step 3:

Finally the two Helium-3 nuclei fuse together to form one Helium nucleus, emitting 2 protons along with it.

 

 

 

Overall the net reaction is four hydrogen nuclei forming a single helium nucleus, two positrons, two neutrinos, and a lot of energy.