Abundance of live Pu-244 in deep-sea reservoirs on Earth points to rarity of actinide nucleosynthesis

作者：Wallner A^*; Faestermann T; Feige J; Feldstein C; Knie K; Korschinek G; Kutschera W; Ofan A; Paul M; Quinto F; Rugel G; Steier P

来源：Nature Communications, 2015, 6(1): 5956.

DOI：10.1038/ncomms6956

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.

• 出版日期2015-1