Ch. 14.2 Nuclear Fusion in the Sun
-Nuclear fission splits a nucleus into smaller nuclei, while nuclear fusion combines smaller
nuclei into a larger nucleus.
-Nuclear fusion occurs in core, where energy from process makes it’s way to photosphere,
the outer layer of the sun.
-In the Sun, four hydrogen nuclei (protons) fuse into one helium-4 nucleus by way of the
proton-proton chain. Gamma rays and subatomic particles known as neutrinos and
positrons carry off the energy released in the reaction.
Steps: 1.Two protons fuse to make a deuterium nucleus (1 proton and 1 neutron).
This step occurs twice in the overall reaction.
2. The deuterium nucleus and a proton fuse to make a nucleus of helium-3 (2
protons, 1 neutron). This step also occurs twice.
3. Two helium-3 nuclei fuse to form helium-4 (2 protons, 2 neutrons),
releasing two excess protons in the process.
-Radiative diffusion: the slow outward migration of photons
-Gravitational equilibrium regulates the Sun’s core temperature: A rise in core temperature
triggers a chai