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The OB association origin of galactic cosmic rays

Binns, W. R. and Wiedenbeck, M. E. and Arnould, M. and Cummings, A. C. and de Nolfo, G. A. and Goriely, S. and Israel, M. H. and Leske, R. A. and Mewaldt, R. A. and Stone, E. C. and von Rosenvinge, T. T. (2008) The OB association origin of galactic cosmic rays. New Astronomy Reviews, 52 (7-10). pp. 427-430. ISSN 1387-6473. doi:10.1016/j.newar.2008.05.008.

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The isotopic abundances of neon, iron, and a number of other species in the galactic cosmic rays have been measured using the Cosmic Ray Isotope Spectrometer (CRIS) aboard the NASA Advanced Composition Explorer (ACE) spacecraft. We compare our data to results from two-component Wolf-Rayet (WR) models. The largest deviations of galactic cosmic ray (GCR) isotope ratios from solar-system ratios predicted by these models are ^C12/^O16, ^Ne22/^Ne20, and ^Fe58/^Fe56. Our measured abundance ratios show good agreement with the model predictions. All of our measured isotopic ratios are consistent with a GCR source consisting of ~20% of WR material mixed with ~80% material with solar-system composition. Since WR stars are evolutionary products of OB stars, and most OB stars exist in OB associations, the good agreement of our data with these models strongly suggests that OB associations are the most probable source of at least a substantial fraction of GCRs. In previous work we have shown that the primary ^Ni59 (which is radioactive and decays only by electron-capture) synthesized in supernovae has decayed prior to being accelerated to GCRs, indicating a time interval between nucleosynthesis and acceleration of >10^5 yr. In this paper we describe a scenario that should allow most of the ^Ni59 to decay in the OB association environment and conclude that OB associations are the likely source of most GCRs.

Item Type:Article
Related URLs:
URLURL TypeDescription
Binns, W. R.0000-0001-6110-3407
Wiedenbeck, M. E.0000-0002-2825-3128
Cummings, A. C.0000-0002-3840-7696
de Nolfo, G. A.0000-0002-3677-074X
Israel, M. H.0000-0002-8104-208X
Leske, R. A.0000-0002-0156-2414
Mewaldt, R. A.0000-0003-2178-9111
Stone, E. C.0000-0002-2010-5462
Additional Information:© 2008 Elsevier B.V. This research was supported in part by the National Aeronautics and Space Administration at Caltech, Washington University, the Jet Propulsion Laboratory, and Goddard Space Flight Center (under Grants NAG5-6912 and NAG5-12929).
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Washington UniversityUNSPECIFIED
Subject Keywords:isotopic anomalies; particle-acceleration; superbubble origin; supernova-remnants; massive stars; nucleosynthesis; abundances; metallicity; evolution; galaxy
Issue or Number:7-10
Record Number:CaltechAUTHORS:BINnar08
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13321
Deposited By: Tony Diaz
Deposited On:16 Apr 2009 20:07
Last Modified:08 Nov 2021 22:36

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