Comprehensive nucleosynthesis analysis for ejecta of compact binary mergers

By O. Just, A. Bauswein, Ricard Ardevol Pulpillo, S. Goriely, H. J. M. Astrophysics, Garching, Mppc, Univ. Thessaloniki, Physik Dept., Tum and 1 more. 2014

456 citations recorded by the source corpus.

We present a comprehensive study of r-process element nucleosynthesis in the ejecta of compact binary mergers (CBMs) and their relic black-hole (BH)-torus systems. The evolution of the BH-accretion tori is simulated for seconds with a Newtonian hydrodynamics code including viscosity, pseudo-Newtonian gravity for rotating BHs, and an energy-dependent two-moment closure neutrino transport scheme. The investigated cases are guided by relativistic double neutron star (NS-NS) and NS-BH merger models. Our nucleosynthesis analysis includes the dynamical ejecta expelled during the CBM phase and the neutrino and viscously driven outflows of the relic BH-torus systems. While typically 20 25 % of the initial torus mass are lost by viscously driven outflows, neutrino-powered winds contribute at most another 1 %. Since BH-torus ejecta possess a wide distribution of electron fractions and entropies, they produce heavy elements from A 80 up to the actinides, with relative contributions of A > 130 nuclei being subdominant. The combined ejecta of CBM and BH-torus phases can reproduce the solar abundances amazingly well for A > 90. Varying contributions of the torus ejecta might account for observed variations of lighter elements with 40 < Z < 56 relative to heavier ones, and a considerable reduction of the prompt ejecta compared to the torus ejecta, e.g. in highly asymmetric NS-BH mergers, might explain the composition of heavy-element deficient stars.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/3e69b16bbcbca98ae81bfea964105bc50e30fc7a

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In Astronomy and Astrophysics

Citations in the corpus

The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. II. UV, Optical, and Near-infrared Light Curves and Comparison to Kilonova Models (2017, background): “Our inferred ejecta mass is consistent with that expected for a massive ∼0.1 M torus (e.g., Just et al. 2015; Siegel & Metzger 2017).”
AT 2017gfo: An Anisotropic and Three-component Kilonova Counterpart of GW170817 (2017, background): “If during the merger a disk has formed, on its longer lifetime (100s ms) the spreading due to viscous processes and the subsequent nuclear recombination unbind a fraction of the disk (Metzger et al. 2009; Fernández & Metzger 2013; Metzger & Fernández 2014; Just et al. 2015).”
A Magnetar Origin for the Kilonova Ejecta in GW170817 (2018, background): “…accretion torus, which is created around the central compact object following the merger (e.g., Metzger et al. 2008a, 2009; Fernández & Metzger 2013; Metzger & Fernández 2014; Perego et al. 2014; Just et al. 2015; Martin et al. 2015; Wu et al. 2016; Lippuner et al. 2017; Siegel & Metzger 2017b).”
Dynamical Mass Ejection from Binary Neutron Star Mergers (2016, background): “…2009; Metzger & Fernández 2014; Fernández et al. 2015b; Foucart et al. 2015; Just et al. 2015; Martin et al. 2015), suggest that mergers are likely to eject a large amount of r-process material (Rosswog et al. 1999; Korobkin et al. 2012; Wanajo et al. 2014; Just et al. 2015; Martin et al. 2015).”
r-PROCESS LANTHANIDE PRODUCTION AND HEATING RATES IN KILONOVAE (2015, methodology): “…post-processing full hydrodynamic models as was done in Goriely et al. (2011); Korobkin et al. (2012); Grossman et al. (2014); Wanajo et al. (2014); Just et al. (2015); Martin et al. (2015), we use a parametrized approach that allows us to systematically study the impact of different ejecta…”
Three-dimensional GRMHD Simulations of Neutrino-cooled Accretion Disks from Neutron Star Mergers (2017, methodology): “…accretion flow have been performed under the assumption of hydrodynamics, adopting an effective hydrodynamical α−viscosity (Shakura & Sunyaev 1973) in place of self-consistent MHD turbulence (Fernández & Metzger 2013; Metzger & Fernández 2014; Just et al. 2015; Fernández et al. 2015; ?)”
Neutron Star Mergers Might Not Be the Only Source of r-process Elements in the Milky Way (2018, background): “If the central object does not promptly collapse to a black hole, it emits neutrinos that, together with the neutrinos emitted from the disk, can generate a mass outflow similar to neutrino-driven winds in CC SNe (Perego et al. 2014; Martin et al. 2015; Just et al. 2015).”
Long-term GRMHD simulations of neutron star merger accretion discs: implications for electromagnetic counterparts (2018, background): “A small amount of lanthanide-poor mass ejected by a disk around a promptly-formed BH is consistent with previous hydrodynamic disk models (Fernández & Metzger 2013a; Just et al. 2015; F15).”
Formation of Double Neutron Star Systems (2017, background): “…systems is a vital source of chemical enrichment of the interstellar medium with heavy r-process elements such as, for example, gold (e.g. Eichler et al. 1989; Freiburghaus et al. 1999; Wanajo et al. 2014; Rosswog 2015; Just et al. 2015; Hirai et al. 2015; Wu et al. 2016; Beniamini et al. 2016b).”
Progenitors of gravitational wave mergers: binary evolution with the stellar grid-based code ComBinE (2018, background): “…also lead to chemical enrichment of the interstellar medium by heavy r-process elements which decay and power an electromagnetic transient termed ‘macronova’ or ‘kilonova’ (e.g. Lattimer & Schramm 1974; Kulkarni 2005; Metzger et al. 2010; Rosswog 2015; Just et al. 2015; Abbott et al. 2017c).”
Kilonova light curves from the disc wind outflows of compact object mergers (2014, background): “Viscous and nuclear heating during accretion can drive winds that unbind a significant fraction of the disc (Lee, Ramirez-Ruiz & López-Cámara 2009; Fernández & Metzger 2013a; Just et al. 2015).”