THE SOURCE COMPOSITION OF COSMIC-RAYS AND ITS RELATION TO SUPERNOVA EXPLOSIONS

A mechanism for the formation of the source composition of galactic cosmic rays is proposed by taking into account the observed data on the chemical abundances of the cosmic ray source matter. Lanthanide and siderophile elements in the source composition may have been mainly supplied from the product of the r-process associated with massive supernovae classified as type II stellar explosions, while both refractory and low-volatile elements may have originally come from the ejecta of type I supernovae or red-giant stars. Before these elements are accelerated to cosmic ray energies, they seem to have been condensed in forming: the cosmic ray source matter somewhere in the galactic space. While being condensed into this matter, most of the volatile elements such as H, He, C, N, O and others must have been efficiently lost from tile cosmic ray source matter.