Cosmic-ray nucleosynthesis and the infall rate of extragalactic matter in the solar neighborhood

Abstract

view Abstract Citations (85) References (137) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Cosmic-ray nucleosynthesis and the infall rate of extragalactic matter in the solar neighborhood. Reeves, H. ; Meyer, J. -P. Abstract An up-to-date discussion of the galactic abundances of lithium, beryllium, and boron is presented. The observed galactic abundances of these elements remain surprisingly constant in time, at values significantly lower than predictions made by conventional models of closed galactic evolution. This fact suggests that intergalactic hydrogen may enter our neighborhood. A local infall rate of about 2 solar masses per billion years per sq pc is favored; the rather large uncertainties in this rate are discussed. The measured ratios of element and isotope abundances among the light elements suggest that the average energy spectrum of fast particles in our galactic neighborhood turns up below 50-100 MeV per nucleon. Such a turnup implies that two source families for cosmic rays must exist, perhaps supernovae and ordinary stars. In carbonaceous chondrites, not only boron, but apparently also beryllium and perhaps even lithium, seem to be enriched beyond their stellar abundance values. And even after many years of study, the origin of Li-7 remains uncertain. Publication: The Astrophysical Journal Pub Date: December 1978 DOI: 10.1086/156646 Bibcode: 1978ApJ...226..613R Keywords: Abundance; Cosmic Rays; Galactic Evolution; Intergalactic Media; Nuclear Fusion; Beryllium 9; Boron Isotopes; Carbonaceous Chondrites; Hydrogen Atoms; Lithium Isotopes; Meteoritic Composition; Spallation; Space Radiation; Cosmic Rays:Nucleosynthesis; Element Abundances:Galaxy; Element Abundances:Solar Neighborhood full text sources ADS |