The source charge and isotopic abundances of cosmic rays with Z = 9-16 - A study using new fragmentation cross sections

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168268· OSTI ID:6905076

Webber, W R; Gupta, M; Soutoul, A; Ferrando, P ^[1]

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1. New Hampshire Univ., Durham (USA) CEA, Service d'Astrophysique, Gif-sur-Yvette (France)

The cosmic ray source charge and isotopic abundances for charges with Z = 9-16 are reexamined using newly measured fragmentation cross sections in a standard Galactic propagation model. Compared with earlier studies, the cosmic-ray data are now consistent with no excess of Si-29 and Si-30 in the source relative to the solar coronal abundances. The excess of Mg-25 and Mg-26 is now about 1 sigma or less relative to solar coronal isotopic abundances, leaving Ne-22 as the only clearly established neutron-rich isotopic excess in the cosmic ray source. Better estimates of the source abundances of elements obtained using the new cross sections permit the conclusion that high first ionization potential (FIP) elements have a wide spread of compositional differences in the cosmic-ray source relative to solar coronal abundances, whereas elements with a low FIP have a composition similar to the solar corona. 28 refs.

• OSTI ID: 6905076
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 348; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ATMOSPHERES
CHEMICAL COMPOSITION
COSMIC RADIATION
COSMIC RAY SOURCES
ELEMENT ABUNDANCE
FRAGMENTATION
GALAXIES
IONIZATION
IONIZING RADIATIONS
ISOTOPE RATIO
MATHEMATICAL MODELS
MILKY WAY
ORIGIN
RADIATIONS
SOLAR CORONA
STELLAR ATMOSPHERES
STELLAR CORONAE