Neon burning process

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Nuclear processes

Radioactive decay processes Alpha decay Beta decay Cluster decay Double beta decay Double electron capture Electron capture Gamma radiation Internal conversion Isomeric transition Neutron emission Positron emission Proton emission Spontaneous fission Nucleosynthesis Nuclear fusion Proton-proton chain reaction CNO cycle Triple alpha process Carbon burning process Neon burning process Oxygen burning process Silicon burning process Neutron capture The R-process The S-process Proton capture: The P-process The Rp-process Spallation

The neon burning process is a set of nuclear fusion reactions that take place in massive stars (at least 8 M_Sun). Neon burning requires high temperatures and densities (around 1.2×10⁹ K and 4×10⁹ kg/m³).

At such high temperatures photodisintegration becomes a significant effect, so some neon nuclei decompose, releasing alpha particles thusly:

²⁰Ne + γ → ¹⁶O + ⁴He

These alpha particles can be recycled to produce magnesium-24

²⁰Ne + ⁴He → ²⁴Mg + γ

Alternatively

²⁰Ne(n,γ)²¹Ne(⁴He,n)²⁴Mg

where the neutron produced in the second step can be recycled in the first.

Neon burning takes place after carbon burning has consumed all carbon in the core and built up a new oxygen/neon/magnesium core. The core cools down, and gravitational pressure compresses it, increasing density and temperature up to the ignition point of neon burning.

During neon burning, oxygen and magnesium accumulate in the central core while neon is consumed. After a few years the star consumes all its neon and the core cools down again. Again, gravitational pressure takes over and compress the central core, increasing its density and temperature until oxygen burning process can start.