Editing CNO cycle (section)

== Hot CNO cycles ==
Under conditions of higher temperature and pressure, such as those found in [[nova]]e and [[X-ray burster|X-ray bursts]], the rate of proton captures exceeds the rate of beta-decay, pushing the burning to the [[nuclear drip line|proton drip line]]. The essential idea is that a radioactive species will capture a proton before it can beta decay, opening new nuclear burning pathways that are otherwise inaccessible. Because of the higher temperatures involved, these catalytic cycles are typically referred to as the hot CNO cycles; because the timescales are limited by beta decays instead of [[proton capture]]s, they are also called the beta-limited CNO cycles.{{clarify|date=August 2015}}

=== HCNO-I ===
The difference between the CNO-I cycle and the HCNO-I cycle is that {{nuclide|nitrogen|13|link=yes}} captures a proton instead of decaying, leading to the total sequence
:{{nuclide|carbon|12|link=yes}}→{{nuclide|nitrogen|13|link=yes}}→{{nuclide|oxygen|14|link=yes}}→{{nuclide|nitrogen|14|link=yes}}→{{nuclide|oxygen|15|link=yes}}→{{nuclide|nitrogen|15|link=yes}}→{{nuclide|carbon|12}}

In detail:

:{| border="0"
|- style="height:2em;"
|{{nuclide|carbon|12}}&nbsp;||+&nbsp;||{{nuclide|hydrogen|1}}&nbsp;||→&nbsp;||{{nuclide|nitrogen|13}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|link=yes|Gamma}}}}&nbsp;||&nbsp;||&nbsp;||+&nbsp;||{{val|1.95|ul=MeV}}
|- style="height:2em;"
|{{nuclide|nitrogen|13}}&nbsp;||+&nbsp;||{{nuclide|hydrogen|1}}&nbsp;||→&nbsp;||{{nuclide|oxygen|14}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Gamma}}}}&nbsp;||&nbsp;||&nbsp;||+&nbsp;||{{val|4.63|u=MeV}}
|- style="height:2em;"
|{{nuclide|oxygen|14}}&nbsp;||&nbsp;||&nbsp;||→&nbsp;||{{nuclide|nitrogen|14}}&nbsp;||+&nbsp;||{{SubatomicParticle|link=yes|Positron}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|link=yes|Electron Neutrino}}}}&nbsp;||+&nbsp;||{{val|5.14|u=MeV}}||([[half-life]] of 70.641 seconds)
|- style="height:2em;"
|{{nuclide|nitrogen|14}}&nbsp;||+&nbsp;||{{nuclide|hydrogen|1}}&nbsp;||→&nbsp;||{{nuclide|oxygen|15}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Gamma}}}}&nbsp;||&nbsp;||&nbsp;||+&nbsp;||{{val|7.35|u=MeV}}
|- style="height:2em;"
|{{nuclide|oxygen|15}}&nbsp;||&nbsp;||&nbsp;||→&nbsp;||{{nuclide|nitrogen|15}}&nbsp;||+&nbsp;||{{SubatomicParticle|Positron}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Electron Neutrino}}}}&nbsp;||+&nbsp;||{{val|2.75|u=MeV}}||(half-life of 122.24 seconds)
|- style="height:2em;"
|{{nuclide|nitrogen|15}}&nbsp;||+&nbsp;||{{nuclide|hydrogen|1}}&nbsp;||→&nbsp;||{{nuclide|carbon|12}}&nbsp;||+&nbsp;||{{nuclide|helium|4}}&nbsp;||&nbsp;||&nbsp;||+&nbsp;||{{val|4.96|u=MeV}}
|}

=== HCNO-II ===
The notable difference between the CNO-II cycle and the HCNO-II cycle is that {{nuclide|fluorine|17|link=yes}} captures a proton instead of decaying, and neon is produced in a subsequent reaction on {{nuclide|fluorine|18|link=yes}}, leading to the total sequence

:{{nuclide|nitrogen|15|link=yes}}→{{nuclide|oxygen|16|link=yes}}→{{nuclide|fluorine|17|link=yes}}→{{nuclide|neon|18|link=yes}}→{{nuclide|fluorine|18|link=yes}}→{{nuclide|oxygen|15|link=yes}}→{{nuclide|nitrogen|15}}

In detail:

:{| border="0"
|- style="height:2em;"
|{{nuclide|nitrogen|15}}&nbsp;||+&nbsp;||{{nuclide|hydrogen|1}}&nbsp;||→&nbsp;||{{nuclide|oxygen|16}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Gamma}}}}&nbsp;||&nbsp;||&nbsp;||+&nbsp;||{{val|12.13|u=MeV}}
|- style="height:2em;"
|{{nuclide|oxygen|16}}&nbsp;||+&nbsp;||{{nuclide|hydrogen|1}}&nbsp;||→&nbsp;||{{nuclide|fluorine|17}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Gamma}}}}&nbsp;||&nbsp;||&nbsp;||+&nbsp;||{{val|0.60|u=MeV}}
|- style="height:2em;"
|{{nuclide|fluorine|17}}&nbsp;||+&nbsp;||{{nuclide|hydrogen|1}}&nbsp;||→&nbsp;||{{nuclide|neon|18}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Gamma}}}}&nbsp;||&nbsp;||&nbsp;||+&nbsp;||{{val|3.92|u=MeV}}
|- style="height:2em;"
|{{nuclide|neon|18}}&nbsp;||&nbsp;||&nbsp;||→&nbsp;||{{nuclide|fluorine|18}}&nbsp;||+&nbsp;||{{SubatomicParticle|Positron}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Electron Neutrino}}}}&nbsp;||+&nbsp;||{{val|4.44|u=MeV}}||(half-life of 1.672 seconds)
|- style="height:2em;"
|{{nuclide|fluorine|18}}&nbsp;||+&nbsp;||{{nuclide|hydrogen|1}}&nbsp;||→&nbsp;||{{nuclide|oxygen|15}}&nbsp;||+&nbsp;||{{nuclide|helium|4}}&nbsp;||&nbsp;||&nbsp;||+&nbsp;||{{val|2.88|u=MeV}}
|- style="height:2em;"
|{{nuclide|oxygen|15}}&nbsp;||&nbsp;||&nbsp;||→&nbsp;||{{nuclide|nitrogen|15}}&nbsp;||+&nbsp;||{{SubatomicParticle|Positron}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Electron Neutrino}}}}&nbsp;||+&nbsp;||{{val|2.75|u=MeV}}||(half-life of 122.24 seconds)
|}

=== HCNO-III ===
An alternative to the HCNO-II cycle is that {{nuclide|fluorine|18|link=yes}} captures a proton moving towards higher mass and using the same helium production mechanism as the CNO-IV cycle as
:{{nuclide|fluorine|18}}→{{nuclide|neon|19|link=yes}}→{{nuclide|fluorine|19|link=yes}}→{{nuclide|oxygen|16|link=yes}}→{{nuclide|fluorine|17|link=yes}}→{{nuclide|neon|18|link=yes}}→{{nuclide|fluorine|18}}

In detail:

:{| border="0"
|- style="height:2em;"
|{{nuclide|fluorine|18}}&nbsp;||+&nbsp;||{{nuclide|hydrogen|1}}&nbsp;||→&nbsp;||{{nuclide|neon|19}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Gamma}}}}&nbsp;||&nbsp;||&nbsp;||+&nbsp;||{{val|6.41|u=MeV}}
|- style="height:2em;"
|{{nuclide|neon|19}}&nbsp;||&nbsp;||&nbsp;||→&nbsp;||{{nuclide|fluorine|19}}&nbsp;||+&nbsp;||{{SubatomicParticle|Positron}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Electron Neutrino}}}}&nbsp;||+&nbsp;||{{val|3.32|u=MeV}}||(half-life of 17.22 seconds)
|- style="height:2em;"
|{{nuclide|fluorine|19}}&nbsp;||+&nbsp;||{{nuclide|hydrogen|1}}&nbsp;||→&nbsp;||{{nuclide|oxygen|16}}&nbsp;||+&nbsp;||{{nuclide|helium|4}}&nbsp;||&nbsp;||&nbsp;||+&nbsp;||{{val|8.11|u=MeV}}
|- style="height:2em;"
|{{nuclide|oxygen|16}}&nbsp;||+&nbsp;||{{nuclide|hydrogen|1}}&nbsp;||→&nbsp;||{{nuclide|fluorine|17}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Gamma}}}}&nbsp;||&nbsp;||&nbsp;||+&nbsp;||{{val|0.60|u=MeV}}
|- style="height:2em;"
|{{nuclide|fluorine|17}}&nbsp;||+&nbsp;||{{nuclide|hydrogen|1}}&nbsp;||→&nbsp;||{{nuclide|neon|18}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Gamma}}}}&nbsp;||&nbsp;||&nbsp;||+&nbsp;||{{val|3.92|u=MeV}}
|- style="height:2em;"
|{{nuclide|neon|18}}&nbsp;||&nbsp;||&nbsp;||→&nbsp;||{{nuclide|fluorine|18}}&nbsp;||+&nbsp;||{{SubatomicParticle|Positron}}&nbsp;||+&nbsp;||{{math|{{SubatomicParticle|Electron Neutrino}}}}&nbsp;||+&nbsp;||{{val|4.44|u=MeV}}||(half-life of 1.672 seconds)
|}