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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 Koll^1,2,3, Anton Wallner^2,3, 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