Nucleosynthesis of CNO Isotopes

Abstract

The origin of the seven stable isotopes of carbon, nitrogen, and oxygen remains an unsolved problem. Current views as to the mechanisms of nucleosynthesis of these nuclei indicate a collective history which is extremely complex. Theoretical studies have revealed that quite varied astrophysical sites can contribute significantly to their production, including CNO-cycle hydrogen burning, core helium burning, thermal relaxation oscillations associated with double-shell-burning configurations in red giants, nova explosions, and supernova explosions. The relevance of detailed quantitative estimates of contributions from these diverse sites is clear from the discussions presented throughout this session: coupled to increasing observations of CNO elemental and isotopic abundances, such studies can yield important inferences concerning the history of the interstellar medium, the evolution of our galaxy and of other galaxies, the sources of cosmic rays, stellar evolution, and the mechanisms of nova and supernova explosions.