Observational Confirmation of the Sun’s CNO Cycle

Abstract

the RHESSI spacecraft spectrometer indicate that the CNO cycle occurs at the solar surface, in electrical discharges along closed magnetic loops. At the two feet of the loop, H + ions are accelerated to energy levels that surpass Coulomb barriers for the 12 C( 1 H, !) 13 N and 14 N( 1 H, !) 15 O reactions. First x-rays appear along the discharge path. Next annihilation of " + -particles from 13 N and 15 O (t! = 10 m and 2 m) produce bright spots of 0.511 MeV !'s at the loop feet. As 13 C increases from " + -decay of 13 N, the 13 C(#, n) 16 O reaction produces neutrons and then the 2.2 MeV emission line appears from n-capture on 1 H. These results suggest that the CNO cycle changed the 15 N/ 14 N ratio in the solar wind and at the solar surface over geologic time, and this ratio may contain an important historical record of climate changes related to sunspot activity._________________________________