H / He fusion reaction in the sun.?

Question

Everbody in this section probably knows that 2 Hydrogen nuclei (protons) combine to give Helium.

However, although the atomic no. of He is 2, its atomic mass is 4. So where in the reaction do the 2 extra neutrons come in.

Do they arise from protons with electrons stripped out? Then what of all those free electrons, are they just lost as beta particle radiation?

I meant to say "proton with added electron to make a neutron", of course. So where do the free electrons come from? Or is there a supply of free neutrons?

Answer 1

Fusion occurs between deuterium and hydrogen, tritium (T) and hydrogen, deuterium (D) and deuterium, and there is also a cross section for H to H. Now deuterium is an isotope of H with one neutron and tritium is an isotope with 2 neutrons. So the reaction you are thinking about is D+D --> He which gives off some photons.

Answer 2

I could be wrong, but I've been told by a pro recently that Neutron=Proton+Electron is an archaic and no longer accepted hypothesis.

I was originally taught that 4H--->He + Energy or 4amu---2amu + X joules. But that is (I'm assuming) a very simplistic equation, that likely sacrifices a great deal of accuracy to that end. It was a high school physics class and I have not breeched this topic yet in College. If it is accurate, I suppose using E=MC^2 you can calculate the equivalent joules to mass for the 2 missing amu's.

In man-made hydrogen reactors, it is tritium that is used, but the sun has likely similar isotope abundance percentages as what is on teh periodic table and a certain amount of mass is converted to energy so neither scenario negates the relevance of my first paragraph; however uncertain it may be. I wish I could give you more, but I'm my knowledge on the topic is really quite limited.

Answer 3

A neutron is considered to be a proton with an electron. This is shown in beta radiation when electrons come from the nucleus and leave behind an extra proton.

Answer 4

There are actually a couple of mechanisms, usually involving Deuterium and/or Tritium.