Nuclear Reaction In Stars

In the late 1930s hans bethe first recognized that the fusion of hydrogen nuclei to form deuterium is exoergic ie there is a net release of energy and together with subsequent nuclear reactions leads to the synthesis of helium.

Nuclear fission zhongwen first world war opponents. Schematic of the proton proton chain nuclear fusion reaction. This reaction has great importance for stellar evolution. Studies of our own main sequence star the sun reveal that its energy comes from a series of nuclear reactions called the proton proton chain.

Nuclear reactions in main sequence stars. The energy released in previous pp chain reaction is proportional to the 4th power of temperature while that in triple alpha process is proportional to a whooping 17th power of temperature. Fusion reactions are the primary energy source of stars and the mechanism for the nucleosynthesis of the light elements.

Fusion reactions in stars. They influence sensitively the nucleosynthesis of the elements in the earliest stages of the universe and in all the objects formed thereafter and control the associated energy generation neutrino luminosity and evolution of stars. For stars like the sun which have internal temperatures less than fifteen million kelvin the dominant fusion process is proton proton fusionfor more massive stars which can achieve higher temperatures the carbon cycle fusion becomes the dominant mechanism.

Nuclear reactions are at the heart of nuclear astrophysics.