Neon burning process
1616027
202020018
2008-03-30T10:18:21Z
62.10.253.110
+ it
The '''neon burning process''' is a set of [[nuclear fusion]] reactions that take place in massive [[star]]s (at least 8 [[Solar mass|M<sub>Sun</sub>]]). Neon burning requires high temperatures and [[density|densities]] (around 1.2×10<sup>9</sup> [[kelvin|K]] and 4×10<sup>9</sup> kg/m<sup>3</sup>).
At such high temperatures [[photodisintegration]] becomes a significant effect, so some neon [[atomic nucleus|nuclei]] decompose, releasing [[alpha particle]]s:
<!-- Autogenerated using Phykiformulae 0.10 by [[User:SkyLined]]
Ne-20 + y -> O-16 + He
Ne-20 + He -> Mg-24 + y
7 Alternatively:
Ne-20 + n -> Ne-21 + y
Ne-21 + He -> Mg-24 + n
-->:{| border="0"
|- style="height:2em;"
|[[Neon-20|{{nuclide|neon|20}}]] ||+ ||[[Gamma ray|γ]] ||→ ||[[Oxygen-16|{{nuclide|oxygen|16}}]] ||+ ||[[Helium|{{nuclide|helium|4}}]]
|- style="height:2em;"
|[[Neon-20|{{nuclide|neon|20}}]] ||+ ||[[Helium|{{nuclide|helium|4}}]] ||→ ||[[Magnesium-24|{{nuclide|magnesium|24}}]] ||+ ||[[Gamma ray|γ]]
|- style="height:2em;"
|colspan=7|Alternatively:
|- style="height:2em;"
|[[Neon-20|{{nuclide|neon|20}}]] ||+ ||[[Neutron|n<sup>0</sup>]] ||→ ||[[Neon-21|{{nuclide|neon|21}}]] ||+ ||[[Gamma ray|γ]]
|- style="height:2em;"
|[[Neon-21|{{nuclide|neon|21}}]] ||+ ||[[Helium|{{nuclide|helium|4}}]] ||→ ||[[Magnesium-24|{{nuclide|magnesium|24}}]] ||+ ||[[Neutron|n<sup>0</sup>]]
|}
Where the neutron consumed in the first step is regenerated in the second.
Neon burning takes place after [[carbon burning process|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 the [[oxygen burning process]] can start.
{{Nuclear processes}}
[[Category:Nucleosynthesis]]
{{star-stub}}
[[de:Neonbrennen]]
[[es:Proceso de combustión del neón]]
[[it:Processo di fusione del neon]]
[[lt:Neono degimo procesas]]
[[pt:Processo de combustão do neônio]]
[[tr:Neonun yanma süreci]]
[[zh:氖燃燒過程]]