Matter from outside our solar system—new insights, Part I: The astrophysical framework

Abstract

Cosmic rays are an interesting sample of galactic matter. The element abundances contain information on the source matter, the acceleration process, and the history of particle propagation in the galaxy. Unfortunately, this information cannot be unlocked completely due to the unknown nature of the acceleration process. However, the cosmic-ray isotopes provide the key for studying the matter at the cosmic-ray source. Is the nucleosynthetic history of this matter the same as matter in our solar system? This long-standing question is beginning to be answered due, at least partly, to the new research results in cosmic-ray physics. The theory of nucleosynthesis for heavy elements during stellar evolution has been reviewed to provide a basis for the interpretation of the differences or similarities between the isotopic composition of cosmic-ray source matter and material from the solar system. Particular attention was devoted to the elements neon, magnesium, and silicon since these are the elements whose isotopes have been studied recently in the cosmic rays and provide the best current information on the composition of the cosmic-ray source matter. (AIP)