Evidence for recent interstellar 60Fe on Earth

Over the last 20 years the long-lived radionuclide 60Fe with a half-life of 2.6 Myr was shown to be an expedient astrophysical tracer to detect freshly synthesized stardust on Earth. The unprecedented sensitivity of Accelerator Mass Spectrometry for 60Fe at The Australian National University (ANU) and Technical University of Munich (TUM) allowed us to detect minute amounts of 60Fe in deep-sea crusts, nodules, sediments and on the Moon [1-5]. These signals, around 2-3 Myr and 6.5-9 Myr before present, were interpreted as a signature from nearby Supernovae which synthesized and ejected 60Fe into the local interstellar medium. Triggered by these findings, ANU and TUM independently analyzed recent surface material for 60Fe, deep-sea sediments and for the first time Antarctic snow, respectively [6, 7]. We find in both terrestrial archives corresponding amounts of recent 60Fe. We will present these discoveries, evaluate the origin of this recent influx and bring it into line with previously reported ancient 60Fe findings.

Keywords

Iron, Earth planet, Radioisotopes, Half-life, Accelerator experimental facilities, Moon, Interstellar magnetic field, Sea bed, Sediments

Citation

Koll, D., Faestermann, T., Feige, J., Fifield, L. K., Froehlich, M. B., Hotchkis, M. A. C., Korschinek, G., Merchel, S., Panjkov, S., Pavetich, S., Tims, S. G., & Wallner, A. (2019). Evidence for recent interstellar 60Fe on earth. Paper presented to the Heavy Ion Accelerator Symposium on Fundamental and Applied Science - 2019, 9-13 September 2019, Department of Nuclear Physics, Australian National University, Canberra, Australia. (pp. 42). Retrieved from: http://hias.anu.edu.au/2019/_files/2019_HIAS_BookOfAbstracts.pdf

URI

https://apo.ansto.gov.au/handle/10238/15294

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