title: Abundance of live ²⁴⁴Pu in deep-sea reservoirs on Earth points to rarity of actinide nucleosynthesis.
abstract: 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.
authors.affiliation: 1] Department of Nuclear Physics, Australian National University, Canberra, Australian Capital Territory 0200, Australia [2] VERA Laboratory, Faculty of Physics, University of Vienna, Währinger Strasse 17, A-1090 Vienna, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Wallner
authors.affiliation: Physik Department, Technische Universität München, D-85747 Garching, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Faestermann
authors.affiliation: VERA Laboratory, Faculty of Physics, University of Vienna, Währinger Strasse 17, A-1090 Vienna, Austria.
authors.forename: J
authors.initials: J
authors.lastname: Feige
authors.affiliation: Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel.
authors.forename: C
authors.initials: C
authors.lastname: Feldstein
authors.affiliation: 1] Physik Department, Technische Universität München, D-85747 Garching, Germany [2] GSI Helmholtz-Zentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Knie
authors.affiliation: Physik Department, Technische Universität München, D-85747 Garching, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Korschinek
authors.affiliation: VERA Laboratory, Faculty of Physics, University of Vienna, Währinger Strasse 17, A-1090 Vienna, Austria.
authors.forename: W
authors.initials: W
authors.lastname: Kutschera
authors.affiliation: Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Ofan
authors.affiliation: Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Paul
authors.affiliation: VERA Laboratory, Faculty of Physics, University of Vienna, Währinger Strasse 17, A-1090 Vienna, Austria.
authors.forename: F
authors.initials: F
authors.lastname: Quinto
authors.affiliation: Physik Department, Technische Universität München, D-85747 Garching, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Rugel
authors.affiliation: VERA Laboratory, Faculty of Physics, University of Vienna, Währinger Strasse 17, A-1090 Vienna, Austria.
authors.forename: P
authors.initials: P
authors.lastname: Steier