Oxygen-burning process

As oxygen burning are a group of nuclear fusion reactions inside massive stars with an initial mass of at least eight solar masses, which by converting oxygen, energy is released. It begins after the lighter elements were consumed by other fusion processes. Requirement for oxygen burning are high temperatures of at least 1.5 × 109 Kelvin and high densities of at least 1010 kg/m3.

When oxygen firing fused either a) an oxygen core with a helium nucleus to neon, or b) an oxygen core 16O with a second to several new nuclei, including sulfur (S), phosphorus (P ), silicon (Si) and magnesium (Mg). It also gamma quanta are γ, n neutrons, hydrogen nuclei 1H ( protons) and alpha particles ( helium nuclei ) 4He free:

A)

This Ne - cores they are usually split again within the Neonbrennens.

B )

During the previous Neonbrennens there is a dead core of oxygen and magnesium formed in the central region of the star. In the absence of further fuel the Neonbrennen comes to a standstill. The radiation pressure is no longer sufficient to counteract the gravitation of the own mass, and the core is further compressed. This causes a renewed temperature and density increase until the ignition temperature is reached for the oxygen burning and the star is stabilized. Around the core is in the so-called shell burning again Neonbrennen a; outwards follow shells with carbon, helium and hydrogen burning.

The oxygen burning lasts only a few years ( in the article Star there is an exemplary time scale for the duration of the individual combustion phases). During this time, the core having silicon accumulates until the oxygen is consumed. Thereafter, the core cools down again, and is compressed by gravity, until the last combustion stage begins, the silicon burn.

Credentials

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

• Astrophysical process