Publication Date:
2016-04-15
Description:
The rate of supernovae in our local Galactic neighbourhood within a distance of about 100 parsecs from Earth is estimated to be one every 2-4 million years, based on the total rate in the Milky Way (2.0 +/- 0.7 per century). Recent massive-star and supernova activity in Earth's vicinity may be traced by radionuclides with half-lives of up to 100 million years, if trapped in interstellar dust grains that penetrate the Solar System. One such radionuclide is (60)Fe (with a half-life of 2.6 million years), which is ejected in supernova explosions and winds from massive stars. Here we report that the (60)Fe signal observed previously in deep-sea crusts is global, extended in time and of interstellar origin from multiple events. We analysed deep-sea archives from all major oceans for (60)Fe deposition via the accretion of interstellar dust particles. Our results reveal (60)Fe interstellar influxes onto Earth at 1.5-3.2 million years ago and at 6.5-8.7 million years ago. The signal measured implies that a few per cent of fresh (60)Fe was captured in dust and deposited on Earth. Our findings indicate multiple supernova and massive-star events during the last ten million years at distances of up to 100 parsecs.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wallner, A -- Feige, J -- Kinoshita, N -- Paul, M -- Fifield, L K -- Golser, R -- Honda, M -- Linnemann, U -- Matsuzaki, H -- Merchel, S -- Rugel, G -- Tims, S G -- Steier, P -- Yamagata, T -- Winkler, S R -- England -- Nature. 2016 Apr 7;532(7597):69-72. doi: 10.1038/nature17196.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University (ANU), Canberra, Australian Capital Territory 2601, Australia. ; University of Vienna, Faculty of Physics-Isotope Research, VERA Laboratory, Wahringer Strasse 17, 1090 Vienna, Austria. ; Institute of Technology, Shimizu Corporation, Tokyo 135-8530, Japan. ; Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel. ; Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki 305-8577, Japan. ; Senckenberg Collections of Natural History Dresden, GeoPlasmaLab, Konigsbrucker Landstrasse 159, Dresden 01109, Germany. ; MALT (Micro Analysis Laboratory, Tandem accelerator), The University Museum, The University of Tokyo, Tokyo 113-0032, Japan. ; Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Helmholtz Institute for Resource Technology, 01328 Dresden, Germany. ; Graduate School of Integrated Basic Sciences, Nihon University, Tokyo 156-8550, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27078565" target="_blank"〉PubMed〈/a〉
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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