期刊
NATURE COMMUNICATIONS
卷 6, 期 -, 页码 -出版社
NATURE PUBLISHING GROUP
DOI: 10.1038/ncomms6956
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资金
- Austrian Science Fund (FWF) [P20434-N20, I428-N16]
- Israel Science Foundation (ISF) [43/01]
- DFG Cluster of Excellence 'Origin and Structure of the Universe'
- Austrian Science Fund (FWF) [I 428] Funding Source: researchfish
Half of the heavy elements including all actinides are produced in r-process nucleosynthesis, whose sites and history remain a mystery. If continuously produced, the Interstellar Medium is expected to build-up a quasi-steady state of abundances of short-lived nuclides (with half-lives <= 100 My), including actinides produced in r-process nucleosynthesis. Their existence in today's interstellar medium would serve as a radioactive clock and would establish that their production was recent. In particular Pu-244, a radioactive actinide nuclide (half-life = 81 My), can place strong constraints on recent r-process frequency and production yield. Here we report the detection of live interstellar Pu-244, archived in Earth's deep-sea floor during the last 25 My, at abundances lower than expected from continuous production in the Galaxy by about 2 orders of magnitude. This large discrepancy may signal a rarity of actinide r-process nucleosynthesis sites, compatible with neutron-star mergers or with a small subset of actinide-producing supernovae.
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