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In the CNO cycle, four protons fuse, using carbon, nitrogen, and oxygen isotopes as catalysts, each of which is consumed at one step of the CNO cycle, but re-generated in a later step. The end product is one alpha particle (a stable helium nucleus), two positrons , and two electron neutrinos .
The ‘ CNO cycle’ refers to the Carbon-Nitrogen- Oxygen cycle, a process of stellar nucleosynthesis in which stars on the Main Sequence fuse hydrogen into helium via a six-stage sequence of reactions. This sequence proceeds as follows: A carbon-12 nucleus captures a proton and emits a gamma ray, producing nitrogen-13.
Der Bethe-Weizsäcker-Zyklus (auch CN-Zyklus, CNO-Zyklus, CNO-I-Zyklus, Kohlenstoff-Stickstoff-Zyklus) ist eine der acht Fusionsreaktionen des so genannten Wasserstoffbrennens, durch die Sterne Wasserstoff in Helium umwandeln; die anderen sind die Proton-Proton-Reaktion sowie weitere mögliche CNO-Zyklen, die allerdings bei noch höheren ...
CNO cycle, sequence of thermonuclear reactions that provides most of the energy radiated by the hotter stars. It is only a minor source of energy for the Sun and does not operate at all in very cool stars. Four hydrogen nuclei are in effect converted into one helium nucleus, a fraction of the mass.
- The Editors of Encyclopaedia Britannica
The CNO Cycle. The PP chain is the most important energy production mechanism for normal stars having masses comparable to the Sun or less. For more massive stars the PP chain can still occur, but there is another sequence of reactions that becomes more favorable for converting hydrogen to helium.
1. Sept. 2019 · Proton-Proton Chain. The simplest reaction that occurs in stars is the conversion of hydrogen into helium - a process known as the proton-proton chain and requires a core temperature of at least 10 million K. In this process six hydrogen atoms are needed to create one helium nucleus of two protons and two neutrons.
In higher-mass stars, the dominant energy production process is the CNO cycle, which is a catalytic cycle that uses nuclei of carbon, nitrogen and oxygen as intermediaries and in the end produces a helium nucleus as with the proton-proton chain. CNO reaction is a very temperature sensitive process. [3] .