| Literature DB >> 33986180 |
A Wallner1,2, M B Froehlich3, M A C Hotchkis4, N Kinoshita5, M Paul6, M Martschini3, S Pavetich3, S G Tims3, N Kivel7, D Schumann7, M Honda8, H Matsuzaki9, T Yamagata9.
Abstract
Half of the chemical elements heavier than iron are produced by the rapid neutron capture process (r-process). The sites and yields of this process are disputed, with candidates including some types of supernovae (SNe) and mergers of neutron stars. We search for two isotopic signatures in a sample of Pacific Ocean crust-iron-60 (60Fe) (half-life, 2.6 million years), which is predominantly produced in massive stars and ejected in supernova explosions, and plutonium-244 (244Pu) (half-life, 80.6 million years), which is produced solely in r-process events. We detect two distinct influxes of 60Fe to Earth in the last 10 million years and accompanying lower quantities of 244Pu. The 244Pu/60Fe influx ratios are similar for both events. The 244Pu influx is lower than expected if SNe dominate r-process nucleosynthesis, which implies some contribution from other sources.Entities:
Year: 2021 PMID: 33986180 DOI: 10.1126/science.aax3972
Source DB: PubMed Journal: Science ISSN: 0036-8075 Impact factor: 47.728