Bethe–Weizsäcker cycle

E75704

CNO cycle hydrogen burning process stellar nuclear fusion process

The Bethe–Weizsäcker cycle is a nuclear fusion process in stars, particularly massive ones, where hydrogen is converted into helium through a catalytic cycle involving carbon, nitrogen, and oxygen nuclei.

Aliases (4)

Statements (48)

Predicate	Object
instanceOf	CNO cycle → hydrogen burning process → stellar nuclear fusion process →
alsoKnownAs	CNO cycle → carbon–nitrogen–oxygen cycle →
betaDecayInvolves	electron neutrino emission → positron emission →
comparedWith	proton–proton chain →
conserves	carbon-12 nucleus as a catalyst →
converts	hydrogen into helium →
dependsOn	metallicity of the star →
describedIn	stellar structure and evolution theory →
dominantIn	high-temperature stellar interiors → massive main-sequence stars →
dominatesOver	proton–proton chain in high-mass stars →
energySourceFor	massive stars →
field	astrophysics → nuclear physics →
hasSubprocess	CNO-I cycle → CNO-II cycle → CNO-III cycle →
influences	mass–luminosity relation for massive stars → stellar lifetimes of massive stars →
involves	carbon-12 → carbon-13 → nitrogen-13 → nitrogen-14 → nitrogen-15 → oxygen-15 →
mechanismType	catalytic cycle →
namedAfter	Carl Friedrich von Weizsäcker → Hans Bethe →
netEffect	four protons fused into one helium-4 nucleus → release of energy via mass–energy conversion →
occursIn	stellar cores →
partOf	hydrogen burning in stars → stellar nucleosynthesis →
produces	gamma rays → helium-4 → neutrinos →
reactionOrder	sequence of proton captures and beta decays →
requires	core temperatures above about 15 million kelvin →
role	explains energy generation in hot, massive stars →
temperatureSensitivity	strongly temperature dependent (approximately T^17 or higher in some regimes) →
timePeriodOfDevelopment	1930s →
usesAsCatalyst	carbon nuclei → nitrogen nuclei → oxygen nuclei →

Referenced by (6)

Subject (surface form when different)	Predicate
Bethe–Weizsäcker cycle ("CNO-I cycle") → Bethe–Weizsäcker cycle ("CNO-II cycle") → Bethe–Weizsäcker cycle ("CNO-III cycle") →	hasSubprocess
Hans Bethe → Hans Bethe →	notableWork
Bethe–Weizsäcker cycle ("CNO cycle") →	alsoKnownAs