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Wallner A, Froehlich MB, Hotchkis MAC, Kinoshita N, Paul M, Martschini M, Pavetich S, Tims SG, Kivel N, Schumann D, Honda M, Matsuzaki H, Yamagata T. 60Fe and 244Pu deposited on Earth constrain the r-process yields of recent nearby supernovae. Science 2021; 372:742-745. [PMID: 33986180 DOI: 10.1126/science.aax3972] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 04/12/2021] [Indexed: 11/02/2022]
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.
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Affiliation(s)
- A Wallner
- Department of Nuclear Physics, Research School of Physics, Australian National University, Canberra, ACT 2601, Australia. .,Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, 01328 Dresden, Germany
| | - M B Froehlich
- Department of Nuclear Physics, Research School of Physics, Australian National University, Canberra, ACT 2601, Australia
| | - M A C Hotchkis
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia
| | - N Kinoshita
- Institute of Technology, Shimizu Corporation, Tokyo 135-8530, Japan
| | - M Paul
- Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - M Martschini
- Department of Nuclear Physics, Research School of Physics, Australian National University, Canberra, ACT 2601, Australia
| | - S Pavetich
- Department of Nuclear Physics, Research School of Physics, Australian National University, Canberra, ACT 2601, Australia
| | - S G Tims
- Department of Nuclear Physics, Research School of Physics, Australian National University, Canberra, ACT 2601, Australia
| | - N Kivel
- Laboratory of Radiochemistry, Department for Nuclear Energy and Safety, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - D Schumann
- Laboratory of Radiochemistry, Department for Nuclear Energy and Safety, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - M Honda
- Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki 305-8577, Japan
| | - H Matsuzaki
- Micro Analysis Laboratory, Tandem Accelerator, The University Museum, The University of Tokyo, Tokyo 113-0032, Japan
| | - T Yamagata
- Micro Analysis Laboratory, Tandem Accelerator, The University Museum, The University of Tokyo, Tokyo 113-0032, Japan
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Côté B, Eichler M, Yagüe López A, Vassh N, Mumpower MR, Világos B, Soós B, Arcones A, Sprouse TM, Surman R, Pignatari M, Pető MK, Wehmeyer B, Rauscher T, Lugaro M. 129I and 247Cm in meteorites constrain the last astrophysical source of solar r-process elements. Science 2021; 371:945-948. [PMID: 33632846 DOI: 10.1126/science.aba1111] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 01/25/2021] [Indexed: 11/03/2022]
Abstract
The composition of the early Solar System can be inferred from meteorites. Many elements heavier than iron were formed by the rapid neutron capture process (r-process), but the astrophysical sources where this occurred remain poorly understood. We demonstrate that the near-identical half-lives [Formula: see text] of the radioactive r-process nuclei iodine-129 and curium-247 preserve their ratio, irrespective of the time between production and incorporation into the Solar System. We constrain the last r-process source by comparing the measured meteoritic ratio 129I/247Cm = 438 ± 184 with nucleosynthesis calculations based on neutron star merger and magneto-rotational supernova simulations. Moderately neutron-rich conditions, often found in merger disk ejecta simulations, are most consistent with the meteoritic value. Uncertain nuclear physics data limit our confidence in this conclusion.
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Affiliation(s)
- Benoit Côté
- Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network, Konkoly Observatory, 1121 Budapest, Hungary. .,Institute of Physics, Eötvös Loránd University, 1117 Budapest, Hungary.,National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - Marius Eichler
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Andrés Yagüe López
- Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network, Konkoly Observatory, 1121 Budapest, Hungary
| | - Nicole Vassh
- Department of Physics, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Matthew R Mumpower
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.,Center for Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Blanka Világos
- Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network, Konkoly Observatory, 1121 Budapest, Hungary.,Institute of Physics, Eötvös Loránd University, 1117 Budapest, Hungary
| | - Benjámin Soós
- Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network, Konkoly Observatory, 1121 Budapest, Hungary.,Institute of Physics, Eötvös Loránd University, 1117 Budapest, Hungary
| | - Almudena Arcones
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany.,GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
| | - Trevor M Sprouse
- Department of Physics, University of Notre Dame, Notre Dame, IN 46556, USA.,Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Rebecca Surman
- Department of Physics, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Marco Pignatari
- E.A. Milne Centre for Astrophysics, University of Hull, Hull HU6 7RX, UK.,Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network, Konkoly Observatory, 1121 Budapest, Hungary
| | - Mária K Pető
- Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network, Konkoly Observatory, 1121 Budapest, Hungary
| | - Benjamin Wehmeyer
- Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network, Konkoly Observatory, 1121 Budapest, Hungary.,Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB, UK
| | - Thomas Rauscher
- Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB, UK.,Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Maria Lugaro
- Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network, Konkoly Observatory, 1121 Budapest, Hungary.,Institute of Physics, Eötvös Loránd University, 1117 Budapest, Hungary.,Monash Centre for Astrophysics, School of Physics and Astronomy, Monash University, Clayton, VIC 3800, Australia
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Abstract
Mendeleev's introduction of the periodic table of elements is one of the most important milestones in the history of chemistry, as it brought order into the known chemical and physical behaviour of the elements. The periodic table can be seen as parallel to the Standard Model in particle physics, in which the elementary particles known today can be ordered according to their intrinsic properties. The underlying fundamental theory to describe the interactions between particles comes from quantum theory or, more specifically, from quantum field theory and its inherent symmetries. In the periodic table, the elements are placed into a certain period and group based on electronic configurations that originate from the Pauli and Aufbau principles for the electrons surrounding a positively charged nucleus. This order enables us to approximately predict the chemical and physical properties of elements. Apparent anomalies can arise from relativistic effects, partial-screening phenomena (of type lanthanide contraction) and the compact size of the first shell of every l-value. Further, ambiguities in electron configurations and the breakdown of assigning a dominant configuration, owing to configuration mixing and dense spectra for the heaviest elements in the periodic table. For the short-lived transactinides, the nuclear stability becomes an important factor in chemical studies. Nuclear stability, decay rates, spectra and reaction cross sections are also important for predicting the astrophysical origin of the elements, including the production of the heavy elements beyond iron in supernova explosions or neutron-star mergers. In this Perspective, we critically analyse the periodic table of elements and the current status of theoretical predictions and origins for the heaviest elements, which combine both quantum chemistry and physics.
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Abstract
The coalescence of double neutron star (NS-NS) and black hole (BH)-NS binaries are prime sources of gravitational waves (GW) for Advanced LIGO/Virgo and future ground-based detectors. Neutron-rich matter released from such events undergoes rapid neutron capture (r-process) nucleosynthesis as it decompresses into space, enriching our universe with rare heavy elements like gold and platinum. Radioactive decay of these unstable nuclei powers a rapidly evolving, approximately isotropic thermal transient known as a "kilonova", which probes the physical conditions during the merger and its aftermath. Here I review the history and physics of kilonovae, leading to the current paradigm of day-timescale emission at optical wavelengths from lanthanide-free components of the ejecta, followed by week-long emission with a spectral peak in the near-infrared (NIR). These theoretical predictions, as compiled in the original version of this review, were largely confirmed by the transient optical/NIR counterpart discovered to the first NS-NS merger, GW170817, discovered by LIGO/Virgo. Using a simple light curve model to illustrate the essential physical processes and their application to GW170817, I then introduce important variations about the standard picture which may be observable in future mergers. These include ∼ hour-long UV precursor emission, powered by the decay of free neutrons in the outermost ejecta layers or shock-heating of the ejecta by a delayed ultra-relativistic outflow; and enhancement of the luminosity from a long-lived central engine, such as an accreting BH or millisecond magnetar. Joint GW and kilonova observations of GW170817 and future events provide a new avenue to constrain the astrophysical origin of the r-process elements and the equation of state of dense nuclear matter.
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Affiliation(s)
- Brian D. Metzger
- Department of Physics, Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 USA
- Center for Computational Astrophysics, Flatiron Institute, New York, NY 10010 USA
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