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On Al-26 and other short-lived interstellar radioactivitySeveral authors have shown that massive stars exploding at a rate of about three per century can account for a large portion, if not all, of the observed interstellar Al-26. In a separate argument using models of Galactic chemical evolution, Clayton (1984) showed that the Al-26/Al-27 production ratio was not large enough to maintain enough Al-26 in the Galactic disk gas of about 10 exp 10 solar masses having solar composition. We present a resolution of those conflicting arguments. A past history of Galactic infall growing the Galactic disk so dilutes the stable Al-27 concentration that the two approaches can be brought into near agreement. If massive stars dominate the production of Al-26, we suggest that the apparent shortfall of their Al-26/Al-27 yield ratio is to be interpreted as evidence for significant growth of the Galactic disk. We also discuss the implications of these arguments for other extinct radioactivities in meteorites, using I-129 and Sm-146 as examples.
Document ID
19930072495
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Clayton, Donald D.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Hartmann, Dieter H.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Leising, Mark D.
(Clemson Univ. SC, United States)
Date Acquired
August 16, 2013
Publication Date
September 20, 1993
Publication Information
Publication: Astrophysical Journal, Part 2 - Letters
Volume: 415
Issue: 1
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
93A56492
Funding Number(s)
CONTRACT_GRANT: N00014-89-T-2034
CONTRACT_GRANT: NAG5-1578
Distribution Limits
Public
Copyright
Other

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