ASTRO-110 Lecture Notes - Lecture 23: Thermostat, Photon, Radiation Zone
Document Summary
Core consists of a very hot and dense plasma of hydrogen and helium temperature exceeds 15 million k. Density is roughly 160 g/cm3 the plasma consists mostly of bare protons and electrons. Nuclear fusion occurs when atomic nuclei merge together. If the original nuclei are light enough, the mass of the resulting nucleus is less than the sum of the masses of the original nuclei! E=mc2 the missing mass has been converted into energy. If the nucleus gets close enough, it will fall into the well and not roll back (strong force holds them close) the proton-proton chain. A proton and a deuterium nucleus fuse together, yielding 3he and extra energy (in form of gamma ray photon) two 3he nuclei fuse together, yielding 4he (normal) + 2 protons + extra energy. On the earth, nuclear fusion can occur and is only achieved in a thermonuclear explosion.
