Positron-electron anihilation in the Sun

Question

As 75% of the Sun is Hydrogen and 25% Helium and the latter derives from 4 hydrogen atoms where half of protons that formed neutrons expeled positive charges as positrons that anihilated with nearby electrons, so half of electrons are missing too. In that case 12.5% of all electrons and positrons(protons) that are now missing formed very energetic gamma-rays which must have a role in fusion reactions in the core.Maybe they partialy roll back to form electron-positron pairs but how much of energy in the core is due to mass defect of helium and how much of electron-positron anihilation?

Answer 1

The positrons were created from the excess energy of the fusion reaction. So you can't count them in addition to the fusion. It's all part of it. But the loss of the original 2 electrons is included in the total energy budget. When you see a figure like 26.7MeV for 4H -> 1He, that includes the electron loss.

The binding energy released from forming the $\text{He}^4$ nucleus is about $0.03u$. But the energy from removing two electrons is equal to their mass or about $0.001u$. So 3-4% of the contribution is from the electron loss.