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The neon-burning process is a set of nuclear fusion reactions that take place in evolved massive stars with at least 8 Solar masses. Neon burning requires high temperatures and densities (around 1.2×109 K or 100 keV and 4×109 kg/m3).
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At such high temperatures photodisintegration becomes a significant effect, so some neon nuclei decompose, releasing alpha particles:[1]
Alternatively:
20
10Ne
+ n → 21
10Ne
+ γ 21
10Ne
+ 4
2He
→ 24
12Mg
+ n
where the neutron consumed in the first step is regenerated in the second.
Neon burning takes place after carbon burning has consumed all carbon in the core and built up a new oxygen–neon–sodium–magnesium core. The core ceases producing fusion energy and contracts. This contraction increases density and temperature up to the ignition point of neon burning. The increased temperature around the core allows carbon to burn in a shell, and there will be shells burning helium and hydrogen outside.
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 ceases producing fusion energy and contracts. Again, gravitational pressure takes over and compresses the central core, increasing its density and temperature until the oxygen-burning process can start.
See also
- Carbon-burning process
- Oxygen-burning process
References
- Clayton, Donald. Principles of Stellar Evolution and Nucleosynthesis, (1983)
External links
- Arnett, W. D. Advanced evolution of massive stars. V – Neon burning / Astrophysical Journal, vol. 193, Oct. 1, 1974, pt. 1, p. 169–176.
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На других языках
[de] Neonbrennen
Als Neonbrennen bezeichnet man eine Gruppe von Kernfusionsreaktionen im Inneren schwerer Sterne mit einer Ausgangsmasse von mindestens acht Sonnenmassen, bei denen durch die Umwandlung des Ausgangsstoffes Neon Energie freigesetzt wird. Voraussetzung hierfür sind hohe Temperaturen von mindestens 1,2·109 Kelvin und hohe Dichten von mindestens 4·109 kg/m³.- [en] Neon-burning process
[es] Proceso de combustión del neón
El proceso de combustión del neón es un tipo de fusión nuclear que solo ocurre en estrellas masivas (al menos 8 MSolar). La combustión del neón requiere de altas temperaturas y de densidades cerca de 1.2×109 K y 4×109 kg/m³.[ru] Ядерное горение неона
Горение неона — последовальность термоядерных реакций, протекающая в недрах массивных звёзд (не менее 8 солнечных масс). Для данного процесса необходимо наличие высокой температуры и плотности (1,2⋅109 К и 4⋅109 кг/м³).Другой контент может иметь иную лицензию. Перед использованием материалов сайта WikiSort.org внимательно изучите правила лицензирования конкретных элементов наполнения сайта.
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