2016年4月6日
Recent near-Earth supernovae probed by global deposition of interstellar radioactive 60Fe
Nature
- 巻
- 532
- 号
- 7597
- 開始ページ
- 69
- 終了ページ
- 72
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1038/nature17196
- 出版者・発行元
- Nature Publishing Group
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 century1,2). Recent massive-star and supernova activity in Earth's vicinity may be traced by radionuclides with half-lives of up to 100 million years3-6, if trapped in interstellar dust grains that penetrate the Solar System. One such radionuclide is 60Fe (with a half-life of 2.6 million years)7,8, which is ejected in supernova explosions and winds from massive stars1,2,9. Here we report that the 60Fe signal observed previously in deep-sea crusts10,11 is global, extended in time and of interstellar origin from multiple events. We analysed deep-sea archives from all major oceans for 60Fe 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 60Fe 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.
- リンク情報
- ID情報
-
- DOI : 10.1038/nature17196
- ISSN : 1476-4687
- ISSN : 0028-0836
- eISSN : 1476-4687
- ORCIDのPut Code : 55943263
- SCOPUS ID : 84963553713