On the stellar origin of the Ne-22 excess in cosmic rays

Abstract

The Ne-22 excess at a cosmic ray source is considered in terms of an Ne-22-rich component injected and accelerated by carbon-rich Wolf-Rayet stars. The overabundance of Ne-22 relative to Ne-20 predicted at the surface of these stars is estimated to a factor of approximately 120 with regard to solar system abundances. The carbon-rich W-R contribution to the primary cosmic ray flux would have to be at maximum 1/60 in order to produce an Ne-22 excess of about 3 at the cosmic ray source. This component would be energized by strong stellar winds, producing quasi-standing shocks around the W-R stars.