Interstellar 60Fe in Antarctica

Earth is constantly bombarded with extraterrestrial dust containing invaluable information about extraterrestrial processes, such as 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 Fe-60 influx onto Earth by analyzing 500 kg of snow from Antarctica by accelerator mass spectrometry. By the measurement of the cosmogenically produced radionuclide Mn-53, an atomic ratio of Fe-60/Mn-53 = 0.017 was found, significantly above cosmogenic production. After elimination of possible terrestrial sources, such as global fallout, the excess of Fe-60 could only be attributed to interstellar Fe-60 which might originate from the solar neighborhood.