Short-lived 244Pu points to compact binary mergers as sites for heavy r-process nucleosynthesis
Abstract
The origin of heavy elements produced through rapid neutron capture (`r-process’) by seed nuclei is one of the current nucleosynthesis mysteries. Core collapse supernovae (cc-SNe; ref. ) and compact binary mergers are considered as possible sites. The first produces small amounts of material at a high event rate whereas the latter produces large amounts in rare events. Radioactive elements with the right lifetime can break the degeneracy between high-rate/low-yield and low-rate/high-yield scenarios. Among radioactive elements, most interesting is 244Pu (half-life of 81 million years), for which both the current accumulation of live 244Pu particles accreted via interstellar particles in the Earth’s deep-sea floor and the Early Solar System (ESS) abundances have been measured. Interestingly, the estimated 244Pu abundance in the current interstellar medium inferred from deep-sea measurements is significantly lower than that corresponding to the ESS measurements. Here we show that both the current and ESS abundances of 244Pu are naturally explained within the low-rate/high-yield scenario. The inferred event rate remarkably agrees with compact binary merger rates estimated from Galactic neutron star binaries and from short gamma-ray bursts. Furthermore, the ejected mass of r-process elements per event agrees with both theoretical and observational macronova/kilonova estimates.
- Publication:
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Nature Physics
- Pub Date:
- December 2015
- DOI:
- 10.1038/nphys3574
- arXiv:
- arXiv:1510.00711
- Bibcode:
- 2015NatPh..11.1042H
- Keywords:
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- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 11 pages, 7 figures