How does nucleosynthesis work?

Question

Madeline Arroyo · Accepted Answer

Nucleosynthesis is the process by which elements heavier than Hydrogen are created.

Elements lighter than iron release energy if additional nucleons are added to their nuclei. Nucleons are protons and neutrons. This process is called nuclear fusion.

Each element is defined by the number of protons in its nucleus. Nuclei with the same number of protons but different numbers of neutrons are called isotopes. Only some combinations of protons and neutrons are stable.

Nucleosynthesis is the process by which heavier elements are created. There are several different mechanisms for this.

Some lighter elements were created soon after the Big Bang.

One of the fundamental mechanisms is called the proton-proton chain (See Picture below).

It occurs when temperatures and pressures are high enough for two protons to overcome their electrostatic repulsion for the string nuclear force to bind them into Helium 2 also called a di-proton. Most di-protons decay as they are very unstable. Some undergo beta+ decay to become deuterium. This process happens in small stars such as our sun.

Lithium, Beryllium and Boron are reaction by-products in larger stars. These elements are produced by cosmic rays colliding with other elements.

Elements up to Iron are produced in larger stars by fusion.

Elements heavier than Iron are created by neutron capture in supernova explosions.

Cooper Ann · Answer

undefined The fusion reactions that take place in stars, where lighter elements combine to form heavier ones and release energy in the process, are the source of nucleosynthesis, the process of creating new atomic nuclei.