The beryllium and boron abundance in the meteorites - A synthesis in interstellar grains

Abstract

view Abstract Citations (3) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The beryllium and boron abundance in the meteorites: a synthesis in interstellar grains. Dwek, E. Abstract It is suggested that the high abundance of beryllium and boron found in the carbonaceous chondrites is due to the presence of irradiated interstellar graphite grains in those meteorites. The beryllium and boron are produced in the grains by an energetic proton irradiation that occurred at some stage in their lifetime. The identical B-11/B-10 ratio in the earth and in the meteorites and the limited variations in the Li-7/Li-6 ratio between terrestrial and meteoritic samples indicate that these graphite grains were uniformly distributed over large portions of the preplanetary disk. The lower solar photospheric boron and beryllium abundance shows that no BeB-bearing graphite grains were mixed into the sun, pointing to a distinct nuclear origin, quite possibly a synthesis in the interstellar medium by high-energy cosmic rays. The model therefore predicts a solar boron isotopic ratio of 2.3, compatible with that produced in the galactic cosmic-ray propagation model, but distinct from the terrestrial and meteoritic ratio of 4 that is produced in the grains. A measurement of this ratio in the solar photosphere will thus support or disprove the proposed model. Publication: The Astrophysical Journal Pub Date: November 1978 DOI: 10.1086/182814 Bibcode: 1978ApJ...225L.149D Keywords: Abundance; Beryllium; Boron; Carbonaceous Chondrites; Interstellar Matter; Meteoritic Composition; Astronomical Models; Cosmic Dust; Cosmic Rays; Granular Materials; High Energy Interactions; Nuclear Reactions; Photosphere; Solar Atmosphere; ABUNDANCE; BORON; BERYLLIUM; CARBONACEOUS CHONDRITES; METEORITES; GRAINS; ISOTOPIC RATIOS; IRRADIATION; PROTON IRRADIATION; CARBON; SOLAR SYSTEM; EARTH; INTERSTELLAR; ELEMENT RATIOS; LITHIUM; GRAPHITE; COSMIC DUST; SAMPLES; TERRESTRIAL; METEORITE; SUN; Lunar and Planetary Exploration; Meteorites; Element Abundances:Meteorites; Interstellar Matter:Meteorites full text sources ADS |