Encyclopedia > CNO cycle

  Article Content

CNO cycle

The CNO (carbon-nitrogen-oxygen) cycle is one of two fusion reactions by which stars convert hydrogen to helium, the other being the proton-proton chain. While the proton-proton chain is more important in stars the size of the sun or less, theoretical models show that the CNO cycle is the dominant source of energy in heavier stars.

The CNO cycle may also be the dominant cause of nitrogen and oxygen production.

Specifically, the CNO cycle looks like this:

12C + 1H 13N + γ
13N 13C + e+ + νe
13C + 1H 14N + γ
14N + 1H 15O + γ
15O 15N + e+ + νe
15N + 1H 12C + 4He

The cycle results in the fusion of four hydrogen nuclei (1H, protons) into a single helium nucleus (4He, alpha particle), which supplies energy to the star in accordance with Einstein's equation. Ordinary carbon serves as a catalyst in this set of reactions and is regenerated.

See also: Triple-alpha process



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Booker T. and the M.G.s

... soul band that released serious full-length albums during the 1960s. In spite of the steady string of hits, the band broke up in 1971 and attempted to reform in 1975, when ...