Silicon-burning process

As the silicon burning are a group of nuclear fusion reactions inside massive stars with an initial mass of at least eight solar masses, in which the conversion of the starting material silicon energy is released. This requires high temperatures of at least 2.7 · 109 Kelvin and high densities of at least 3.1010 kg / m³.

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It first merge two silicon nuclei 28Si to 56Ni nickel, the νe by two β -decays, releasing positrons e and electron neutrinos over cobalt 56Co is finally converted into iron 56Fe:

In addition to the fusion of silicon and silicon cores can be destroyed by so-called photodisintegration by photons of high energy gamma radiation, which results due to the high temperatures. These processes are endothermic, so escape the star power:

Expiration

The silicon firing following the oxygen burner, which ends when no more oxygen is available for the fusion at the central portion of the star. As at the end of the previous burning phases is the core, which is now rich in silicon, compressed because of the lack of radiation pressure due to gravity. Wherein the temperature and density increase until the condition is reached for the silicon firing. The star thus moves one last time in a hydrostatic equilibrium between gravity and radiation pressure. During silicon burning in the core continue to run in shells around the core, oxygen, neon, carbon, helium and hydrogen burning from.

Firing the silicon represents the end of the thermonuclear fuel processes, as the final products, especially iron 56Fe, the highest binding energy per nucleon own. Elements with larger mass numbers can not be built up by nuclear fusion. Heavier elements are formed by the endothermic s-, r -and p- processes.

The supply of the nuclear fuel inside the silicon is consumed depending on the burning mass of the star in a few hours to a few days. If the central energy source is exhausted, the radiation pressure of the core breaks finally together; the star collapses under its gravity and ends in a supernova of type II

Hydrogen burning helium burning · · · carbon burning Neonbrennen · · oxygen burning silicon burning

• Astrophysical process