GCR Neon Isotopic Abundances: Comparison with Wolf-Rayet Star Models and Meteoritic Abundances

Measurements of the neon isotopic abundances from the ACE-CRIS experiment are presented. These abundances have been obtained in seven energy intervals over the energy range of ~80<E<280 MeV/nucleon. The Ne/Ne source ratio is derived using the measured Ne/Ne abundance as a "tracer" of secondary production of the neon isotopes. We find that the Ne/Ne abundance ratio at the cosmic-ray source is a factor of 5.0±0.2 greater than in the solar wind. The GCR Ne/Ne ratio is also shown to be considerably larger than that found in anomalous cosmic rays, solar energetic particles, most meteoritic samples of matter, and interplanetary dust particles. Recent two-component Wolf-Rayet models provide predictions for the Ne/Ne ratio and other isotope ratios. Comparison of the CRIS neon, iron, and nickel isotopic source abundance ratios with predictions indicate possible enhanced abundances of some neutron-rich nuclides that are expected to accompany the Ne excess.