2015/01/20 by A. Wallner, T. Faestermann, J. Feige +13 · 3 citations
Physics and Astronomy · #Astro and Planetary Science #Astronomical and nuclear sciences #Nuclear physics research studies #astro-ph.SR
paper · pdf · doi:10.1038/ncomms6956
published as Nature Communications 6:5956, 2015
openalex publication_date 2015/01/20 · arxiv created 2015/09/27 · arxiv updated 2015/09/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
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 (244)Pu, 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 (244)Pu, 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.