Freiburg 2024 – wissenschaftliches Programm
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MS: Fachverband Massenspektrometrie
MS 9: Accelerator Mass Spectrometry IV
MS 9.1: Hauptvortrag
Freitag, 15. März 2024, 11:00–11:30, HS 3042
Influx of interstellar 60Fe and 244Pu onto Earth within the last 10 million years recorded in a ferromanganese crust — •Dominik Koll1,2,3, Anton Wallner2,3, Michael Hotchkis4, Sebastian Fichter2, L. Keith Fifield1, Michaela Froehlich1, Michi Hartnett1, Johannes Lachner2, Stefan Pavetich1, Georg Rugel2, Zuzana Slavkovska1, and Steve Tims1 — 1The Australian National University, Canberra, Australia — 2Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — 3TU Dresden, Dresden, Germany — 4Australian Nuclear Science and Technology Organisation, Sydney, Australia
Within the last 25 years, copious evidence was presented for supernova-produced 60Fe influxes onto Earth using accelerator mass spectrometry (AMS); pointing to a near-Earth supernova activity within the last few million years. The rare interstellar r-process radionuclide 244Pu, however, was only recently discovered. The combination of both, supernova-produced 60Fe and r-process 244Pu, allows to shed light onto the nucleosynthesis site of heavy elements in the universe.
A well-characterized and 10Be-dated ferromanganese crust from the Pacific Ocean was used to search for 60Fe and 244Pu abundances with unprecedented time-resolution and sensitivity. The acquired 60Fe profile shows two pronounced peaks of 60Fe influxes with updated timing. A r-process 244Pu influx was discovered with a time-resolution of 1 Myr within the last 10 Myr due to the extraordinarily high total efficiency of Pu AMS of 1% achieved in this project.
Keywords: AMS; 60Fe; 244Pu; Ferromanganese crust; Supernova