scholarly journals Short-lived 244Pu points to compact binary mergers as sites for heavy r-process nucleosynthesis

2015 ◽  
Vol 11 (12) ◽  
pp. 1042-1042 ◽  
Author(s):  
Kenta Hotokezaka ◽  
Tsvi Piran ◽  
Michael Paul
Keyword(s):  
Compact Binary ◽  
Binary Mergers ◽  
R Process

scholarly journals r-Process Nucleosynthesis from Compact Binary Mergers

2021 ◽  
pp. 1-56
Author(s):  
A. Perego ◽  
F. -K. Thielemann ◽  
G. Cescutti
Keyword(s):  
Compact Binary ◽  
Binary Mergers ◽  
R Process

scholarly journals The Dynamics of Binary Neutron Star Mergers and GW170817

2020 ◽  
Vol 70 (1) ◽  
pp. 95-119 ◽  
Author(s):  
David Radice ◽  
Sebastiano Bernuzzi ◽  
Albino Perego
Keyword(s):  
Neutron Star ◽  
Nuclear Astrophysics ◽  
Theoretical Models ◽  
Physical Processes ◽  
Binary Neutron Star ◽  
Compact Binary ◽  
Open Questions ◽  
Binary Mergers ◽  
R Process ◽  
Process Elements

With the first observation of a binary neutron star merger through gravitational waves and light, GW170817, compact binary mergers have now taken the center stage in nuclear astrophysics. They are thought to be one of the main astrophysical sites of production of r-process elements, and merger observations have become a fundamental tool to constrain the properties of matter. Here, we review our current understanding of the dynamics of neutron star mergers in general and of GW170817 in particular. We discuss the physical processes governing the inspiral, merger, and postmerger evolution, and we highlight the connections between these processes, the dynamics, and the multimessenger observables. Finally, we discuss open questions and issues in the field and the need to address them through a combination of better theoretical models and new observations.

scholarly journals Using failed supernovae to constrain the Galactic r-process element production

2019 ◽  
Vol 487 (2) ◽  
pp. 1745-1753 ◽  
Author(s):  
B Wehmeyer ◽  
C Fröhlich ◽  
B Côté ◽  
M Pignatari ◽  
F-K Thielemann
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Large Fraction ◽  
Capture Process ◽  
Compact Binary ◽  
Halo Stars ◽  
The Galaxy ◽  
Binary Mergers ◽  
R Process ◽  
Process Elements

ABSTRACT Rapid neutron capture process (r-process) elements have been detected in a large fraction of metal-poor halo stars, with abundances relative to iron (Fe) that vary by over two orders of magnitude. This scatter is reduced to less than a factor of 3 in younger Galactic disc stars. The large scatter of r-process elements in the early Galaxy suggests that the r-process is made by rare events, like compact binary mergers and rare sub-classes of supernovae. Although being rare, neutron star mergers alone have difficulties to explain the observed enhancement of r-process elements in the lowest metallicity stars compared to Fe. The supernovae producing the two neutron stars already provide a substantial Fe abundance where the r-process ejecta from the merger would be injected. In this work we investigate another complementary scenario, where the r-process occurs in neutron star-black hole mergers in addition to neutron star mergers. Neutron star-black hole mergers would eject similar amounts of r-process matter as neutron star mergers, but only the neutron star progenitor would have produced Fe. Furthermore, a reduced efficiency of Fe production from single stars significantly alters the age–metallicity relation, which shifts the onset of r-process production to lower metallicities. We use the high-resolution [(20 pc)3/cell] inhomogeneous chemical evolution tool ‘ICE’ to study the outcomes of these effects. In our simulations, an adequate combination of neutron star mergers and neutron star-black hole mergers qualitatively reproduces the observed r-process abundances in the Galaxy.

scholarly journals The dynamic ejecta of compact object mergers and eccentric collisions

2013 ◽  
Vol 371 (1992) ◽  
pp. 20120272 ◽  
Author(s):  
Stephan Rosswog
Keyword(s):  
Globular Clusters ◽  
Gamma Ray ◽  
Ambient Medium ◽  
Compact Object ◽  
Solar Mass ◽  
Abundance Pattern ◽  
Compact Binary ◽  
Hydrodynamical Simulations ◽  
Rich Material ◽  
R Process

Compact object mergers eject neutron-rich matter in a number of ways: by the dynamical ejection mediated by gravitational torques, as neutrino-driven winds, and probably also a good fraction of the resulting accretion disc finally becomes unbound by a combination of viscous and nuclear processes. If compact binary mergers indeed produce gamma-ray bursts, there should also be an interaction region where an ultra-relativistic outflow interacts with the neutrino-driven wind and produces moderately relativistic ejecta. Each type of ejecta has different physical properties, and therefore plays a different role for nucleosynthesis and for the electromagnetic (EM) transients that go along with compact object encounters. Here, we focus on the dynamic ejecta and present results for over 30 hydrodynamical simulations of both gravitational wave-driven mergers and parabolic encounters as they may occur in globular clusters. We find that mergers eject approximately 1 per cent of a Solar mass of extremely neutron-rich material. The exact amount, as well as the ejection velocity, depends on the involved masses with asymmetric systems ejecting more material at higher velocities. This material undergoes a robust r-process and both ejecta amount and abundance pattern are consistent with neutron star mergers being a major source of the ‘heavy’ ( A >130) r-process isotopes. Parabolic collisions, especially those between neutron stars and black holes, eject substantially larger amounts of mass, and therefore cannot occur frequently without overproducing gala- ctic r-process matter. We also discuss the EM transients that are powered by radioactive decays within the ejecta (‘macronovae’), and the radio flares that emerge when the ejecta dissipate their large kinetic energies in the ambient medium.

scholarly journals Probing neutrino emission at GeV energies from compact binary mergers with IceCube

2019 ◽  
Author(s):  
Gwenhaël De Wasseige ◽  
Imre Bartos ◽  
Krijn de Vries ◽  
Erin O'Sullivan ◽  
Keyword(s):  
Neutrino Emission ◽  
Compact Binary ◽  
Binary Mergers
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