60Fe and 244Pu deposited on Earth constrain the r-process yields of recent nearby supernovae


60Fe and 244Pu deposited on Earth constrain the r-process yields of recent nearby supernovae

Wallner, A.; Froehlich, M. B.; Hotchkis, M. A. C.; Kinoshita, N.; Paul, M.; Martschini, M.; Pavetich, S.; Tims, S. G.; Kivel, N.; Schumann, D.; Honda, M.; Matsuzaki, H.; Yamagata, T.

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: 60Fe (half-life 2.6 million years, Myr), predominantly produced in massive stars and ejected in SN explosions; and 244Pu, (half-life 80.6 Myr) produced solely in r-process events. We detect two distinct influxes of 60Fe to Earth in the last 10 Myr 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, implying some contribution from other sources.

Keywords: r process; Supernova; interstellar medium; accelerator mass spectrometry; deep-sea archive; 60Fe; 244Pu

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Permalink: https://www.hzdr.de/publications/Publ-32525
Publ.-Id: 32525