CNO cycle

The first reports of the experimental detection of the neutrinos produced by the CNO cycle in the Sun were published in 2020 by the BOREXINO collaboration.[2][9][10] Under typical conditions found in stars, catalytic hydrogen burning by the CNO cycles is limited by proton captures.Because of the long timescales involved, the cold CNO cycles convert hydrogen to helium slowly, allowing them to power stars in quiescent equilibrium for many years.In 2006 it was experimentally measured down to stellar energies, revising the calculated age of globular clusters by around 1 billion years.The total momentum received by the positron and the neutrino is not great enough to cause a significant recoil of the much heavier daughter nucleus[a] and hence, its contribution to kinetic energy of the products, for the precision of values given here, can be neglected.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.
Logarithm of the relative energy output (ε) of proton–proton (p–p), CNO, and triple-α fusion processes at different temperatures (T). The dashed line shows the combined energy generation of the p–p and CNO processes within a star.
Overview of the CNO-I Cycle
A proton reacts with a nucleus causing release of an alpha particle.
Logarithmproton–protontriple-αcarbonnitrogenoxygenHans Albrecht BetheCarl Friedrich von Weizsäckerfusionreactionshydrogenheliumproton–proton chain reactionmassive as the Suncatalytic cycleprotonsalpha particlestablepositronselectron neutrinosannihilate with electronsgamma raysCarl von WeizsäckerHans BetheBOREXINOproton capturesbeta decayradioactive nucleiCarl Friedrich von WeizsäckerRobert BacherMilton Stanley Livingston1967 Nobel Prize in Physicsabundance of nitrogen in the sunhalf-lifepositrons emittedannihilatebeta-decayQ-valueproton captureglobular clustersneutrinosmomentumheavierluminosityfluorineX-ray burstsproton drip line1810Ne1910Nestellar evolutionRed giantmain sequenceAneutronic fusionCold fusionFusion powerNuclear fusionProton–proton chainStellar nucleosynthesisTriple-alpha processJohn Wiley and SonsBibcodeSpringer Science & Business MediaThe Astrophysical Journalvon Weizsäcker, Carl F.Physikalische ZeitschriftBethe, Hans A.Physical ReviewBacher, RobertReviews of Modern PhysicsLivingston, Milton S.Physical Review FocusJohn Wiley & SonsPhysics Letters BBibliographisches InstitutAnnual Review of Astronomy and AstrophysicsNuclear processesRadioactive decayDoubleGamma radiationCluster decayElectron captureInternal conversionIsomeric transitionNeutron emissionPositron emissionProton emissionSpontaneous fissionDeuterium fusionLi burningα processC burningNe burningO burningSi burningr-processs-processp-processrp-processPhotodisintegrationPhotofissionNeutron capture(n-p) reaction