Interstellar Fe 60 in Antarctica

Abstract

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 60Fe influx onto 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 which might originate from the solar neighborhood. Show more