Nuclear combustion of oxygen

Nuclear processes
	Radioactive decay Alpha decay; Beta decay; Cluster decay; Double beta decay; Electronic capture; Dual electronic capture; Gamma radiation; Internal conversion; Isomeric transition; Neutron decay; Positron Decay; Proton decay; Spontaneous division; Nucleosynthesis Thermonuclear reaction Proton-proton cycle; CNO cycle; Triple helium reaction; Helium flash; Nuclear carbon burning; Carbon detonation; Nuclear Burning Neon; Nuclear combustion of silicon; ; Neutron capture r process; s process; ; Proton Capture: p-process; rp process; ; Neutronization; Cleavage reactions;

Nuclear combustion of oxygen is the conventional name for the nuclear fusion of oxygen-16 nuclei in the bowels of stars, heavier than the Sun. It occurs at a temperature of about 1.5⋅10 ⁹ K and a density of about 10 ¹⁰ kg / m ³ . The following are the main reactions of “burning” oxygen :

Reactions with a two-particle final state:

\mathrm {_{8}^{16}O} +\mathrm {_{8}^{16}O} \rightarrow \mathrm {_{14}^{28}Si} +\mathrm {_{2}^{4}He} +Q

{\ displaystyle \ mathrm {_ {8} ^ {16} O} + \ mathrm {_ {8} ^ {16} O} \ rightarrow \ mathrm {_ {14} ^ {28} Si} + \ mathrm {_ {2} ^ {4} He} + Q}

\ mathrm {_8 ^ {16} O} + \ mathrm {_8 ^ {16} O} \ rightarrow \ mathrm {_ {14} ^ {28} Si} + \ mathrm {_2 ^ {4} He} + Q

, Q = 9.594 MeV

\mathrm {_{8}^{16}O} +\mathrm {_{8}^{16}O} \rightarrow \mathrm {_{15}^{31}P} +\mathrm {_{1}^{1}H} +Q

{\ displaystyle \ mathrm {_ {8} ^ {16} O} + \ mathrm {_ {8} ^ {16} O} \ rightarrow \ mathrm {_ {15} ^ {31} P} + \ mathrm {_ {1} ^ {1} H} + Q}

\ mathrm {_8 ^ {16} O} + \ mathrm {_8 ^ {16} O} \ rightarrow \ mathrm {_ {15} ^ {31} P} + \ mathrm {_1 ^ {1} H} + Q

, Q = 7.678 MeV

\mathrm {_{8}^{16}O} +\mathrm {_{8}^{16}O} \rightarrow \mathrm {_{16}^{31}S} +\mathrm {_{0}^{1}n} +Q

{\ displaystyle \ mathrm {_ {8} ^ {16} O} + \ mathrm {_ {8} ^ {16} O} \ rightarrow \ mathrm {_ {16} ^ {31} S} + \ mathrm {_ {0} ^ {1} n} + Q}

\ mathrm {_8 ^ {16} O} + \ mathrm {_8 ^ {16} O} \ rightarrow \ mathrm {_ {16} ^ {31} S} + \ mathrm {_0 ^ {1} n} + Q

, Q = 1,500 MeV

\mathrm {_{8}^{16}O} +\mathrm {_{8}^{16}O} \rightarrow \mathrm {_{15}^{30}P} +\mathrm {_{1}^{2}D} -Q

{\ displaystyle \ mathrm {_ {8} ^ {16} O} + \ mathrm {_ {8} ^ {16} O} \ rightarrow \ mathrm {_ {15} ^ {30} P} + \ mathrm {_ {1} ^ {2} D} -Q}

\ mathrm {_8 ^ {16} O} + \ mathrm {_8 ^ {16} O} \ rightarrow \ mathrm {_ {15} ^ {30} P} + \ mathrm {_1 ^ {2} D} - Q

, Q = 2.409 MeV

\mathrm {_{8}^{16}O} +\mathrm {_{8}^{16}O} \rightarrow \mathrm {_{16}^{32}S} +\gamma +Q

{\ displaystyle \ mathrm {_ {8} ^ {16} O} + \ mathrm {_ {8} ^ {16} O} \ rightarrow \ mathrm {_ {16} ^ {32} S} + \ gamma + Q }

\ mathrm {_8 ^ {16} O} + \ mathrm {_8 ^ {16} O} \ rightarrow \ mathrm {_ {16} ^ {32} S} + \ gamma + Q

, Q = 16.54 MeV

Reactions with a three-particle final state:

\mathrm {_{8}^{16}O} +\mathrm {_{8}^{16}O} \rightarrow \mathrm {_{16}^{30}S} +2\,\mathrm {_{1}^{1}H} +Q

{\ displaystyle \ mathrm {_ {8} ^ {16} O} + \ mathrm {_ {8} ^ {16} O} \ rightarrow \ mathrm {_ {16} ^ {30} S} +2 \, \ mathrm {_ {1} ^ {1} H} + Q}

\ mathrm {_8 ^ {16} O} + \ mathrm {_8 ^ {16} O} \ rightarrow \ mathrm {_ {16} ^ {30} S} + 2 \, \ mathrm {_1 ^ {1} H} + Q

, Q = 0.381 MeV

\mathrm {_{8}^{16}O} +\mathrm {_{8}^{16}O} \rightarrow \mathrm {_{12}^{24}Mg} +2\,\mathrm {_{2}^{4}He} -Q

{\ displaystyle \ mathrm {_ {8} ^ {16} O} + \ mathrm {_ {8} ^ {16} O} \ rightarrow \ mathrm {_ {12} ^ {24} Mg} +2 \, \ mathrm {_ {2} ^ {4} He} -Q}

\ mathrm {_8 ^ {16} O} + \ mathrm {_8 ^ {16} O} \ rightarrow \ mathrm {_ {12} ^ {24} Mg} + 2 \, \ mathrm {_2 ^ {4} He} - Q

, Q = 0.39 MeV

\mathrm {_{8}^{16}O} +\mathrm {_{8}^{16}O} \rightarrow \mathrm {_{13}^{27}Al} +\mathrm {_{2}^{4}He} +\mathrm {_{1}^{1}H} -Q

{\ displaystyle \ mathrm {_ {8} ^ {16} O} + \ mathrm {_ {8} ^ {16} O} \ rightarrow \ mathrm {_ {13} ^ {27} Al} + \ mathrm {_ {2} ^ {4} He} + \ mathrm {_ {1} ^ {1} H} -Q}

\ mathrm {_8 ^ {16} O} + \ mathrm {_8 ^ {16} O} \ rightarrow \ mathrm {_ {13} ^ {27} Al} + \ mathrm {_2 ^ {4} He} + \ mathrm {_1 ^ {1} H} - Q

, Q = 1.99 MeV

For massive stars (more than 25 solar masses), the duration of oxygen burning is estimated at 0.5 years. ^[one]

Notes

↑ http://abyss.uoregon.edu/~js/ast122/lectures/lec18.html "Stars greater than 25 solar masses undergo a more violent end to their lives. Carbon core burning lasts for 600 years for a star of this size . Neon burning for 1 year, oxygen burning about 6 months (ie very fast on astronomical timescales) "

Links

Decay-synthesis conversion of elements
Combustion of carbon and oxygen (neopr.) . Nucleosynthesis in the Universe . Archived February 7, 2003.
http://www.astronet.ru/db/msg/1167293
The origin of stars and chemical elements
Arnett, WD Advanced evolution of massive stars. VI - Oxygen burning / Astrophysical Journal, vol. 194, Dec. 1, 1974, pt. 1, p. 373-383.

[1] ttp://abyss.uoregon.edu/~js/ast122/lectures/lec18.html "Stars greater than 25 solar masses undergo a more violent end to their lives. Carbon core burning lasts for 600 years for a star of this size . Neon burning for 1 year, oxygen burning about 6 months (ie very fast on astronomical timescales) "

Nuclear combustion of oxygen

See also

Notes

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