Interstellar ⁶⁰Fe in Antarctica

Earth is constantly bombarded with extraterrestrial dust containing invaluable information about extraterrestrial processes, e.g. structure formation by stellar explosions or nucleosynthesis, which could be traced back by long-lived radionuclides. Here, we report the very first detection of a recent ⁶⁰Fe influx on Earth by analyzing 500 kg of snow from Antarctica by Accelerator Mass Spectrometry. By the measurement of the cosmogenically produced radionuclide ⁵³Mn, an atomic ratio of ⁶⁰Fe/⁵³Mn=0.017 was found, significantly above cosmogenic production. After elimination of possible terrestrial sources, such as global fallout, the excess of ⁶⁰Fe could only be attributed to interstellar ⁶⁰Fe from the solar neighborhood.