Dynamical mass ejection from binary neutron star mergers: Radiation-hydrodynamics study in general relativity

By Yuichiro Sekiguchi, Kentaro Kiuchi, K. Kyutoku, M. Shibata. 2015

182 citations recorded by the source corpus.

We perform radiation-hydrodynamics simulations of binary neutron star mergers in numerical relativity on the Japanese "K" supercomputer, taking into account neutrino cooling and heating by an updated leakage-plus-transfer scheme for the first time. Neutron stars are modeled by three modern finite-temperature equations of state (EOS) developed by Hempel and his collaborators. We find that the properties of the dynamical ejecta of the merger such as total mass, average electron fraction, and thermal energy depend strongly on the EOS. Only for a soft EOS (the so-called SFHo), the ejecta mass exceeds $0.01M_{\odot}$. In this case, the distribution of the electron fraction of the ejecta becomes broad due to the shock heating during the merger. These properties are well-suited for the production of the solar-like $r$-process abundance. For the other stiff EOS (DD2 and TM1), for which a long-lived massive neutron star is formed after the merger, the ejecta mass is smaller than $0.01M_{\odot}$, although broad electron-fraction distributions are achieved by the positron capture and the neutrino heating.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/d31a19eb557aa50715520e8c75d3c10b0354406b

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Citations in the corpus

Dynamical Mass Ejection from Binary Neutron Star Mergers (2016, methodology): “We find this effect to be appreciable in our simulations, although not as significant as reported by Sekiguchi et al. (2015) and Foucart et al. (2016).”
Colloquium : Superheavy elements: Oganesson and beyond (2019, background): “Numerical simulations show that high neutron densities can be achieved in the dynamical ejecta of this astrophysical scenario (Bauswein et al., 2013; Goriely et al., 2011; Kasen et al., 2017; Korobkin et al., 2012; Radice et al., 2016; Rosswog et al., 1999; Sekiguchi et al., 2015) and in the accreti”
Mass Ejection from the Remnant of a Binary Neutron Star Merger: Viscous-radiation Hydrodynamics Study (2017, methodology): “25 and 0.05–0.5, respectively (Sekiguchi et al. 2015).”
GW170817: Joint Constraint on the Neutron Star Equation of State from Multimessenger Observations (2017, unknown): “2 0.4 ( – ) , shock heated, and re-processed by neutrinos (Sekiguchi et al. 2015; Foucart et al. 2016; Radice et al. 2016).”
Kilonova from post-merger ejecta as an optical and near-infrared counterpart of GW170817 (2017, background): “However, a possible maximum mass of the dynamical ejecta is about 0.01 M⊙ with currently available equation of states (e.g., Hotokezaka et al. 2013; Sekiguchi et al. 2015, 2016; Radice et al. 2016).”
Unequal mass binary neutron star mergers and multimessenger signals (2016, background): “We studied the potential for equal mass binaries to produce a kilonova in recent work [22] (see also [21]) finding the necessary conditions only for the softest EoS studied.”
A burst in a wind bubble and the impact on baryonic ejecta: high-energy gamma-ray flashes and afterglows from fast radio bursts and pulsar-driven supernova remnants (2016, methodology): “The total ejected mass is rather uncertain and depends on the binary parameters; for example, Mext ∼ 10−5 − 10−2 M⊙ for a NS-NS binary based on numerical simulations (see, e.g., Kiuchi et al. 2014; Sekiguchi et al. 2015).”
AT 2017gfo: An Anisotropic and Three-component Kilonova Counterpart of GW170817 (2017, background): “Weak interactions can potentially alter its initial neutron-richness (Sekiguchi et al. 2015; Foucart et al. 2016; Radice et al. 2016; Bovard et al. 2017).”
Binary Neutron Star Mergers: Mass Ejection, Electromagnetic Counterparts, and Nucleosynthesis (2018, background): “…with a microphysical treatment of NS matter and with different levels of approximation for neutrino-radiation effects have also become available (Sekiguchi et al. 2011, 2015, 2016; Palenzuela et al. 2015; Foucart et al. 2016b; Lehner et al. 2016; Radice et al. 2016b; Bovard et al. 2017).”
Signatures of hypermassive neutron star lifetimes on r-process nucleosynthesis in the disc ejecta from neutron star mergers (2017, background): “When neutrino absorption is included in the calculations, a larger fraction of lighter elements (A < 130) can be obtained (e.g., Wanajo et al. 2014; Goriely et al. 2015; Sekiguchi et al. 2015; Radice et al. 2016; Foucart et al. 2016a,b; Roberts et al. 2017).”
RADIOACTIVITY AND THERMALIZATION IN THE EJECTA OF COMPACT OBJECT MERGERS AND THEIR IMPACT ON KILONOVA LIGHT CURVES (2016, background): “Our SPH trajectories are all initially very neutron-rich; however, weak interactions in the aftermath of a merger could raise Ye,0 substantially(Wanajo et al. 2014; Goriely et al. 2015; Sekiguchi et al. 2015).”
Production of the entire range of r-process nuclides by black hole accretion disc outflows from neutron star mergers (2016, background): “…include the effects of e± captures and neutrino irradiation in full general-relativity have shown that the dynamical ejecta can have a wider electron fraction distribution(Ye ∼ 0.1−0.4) than models without weak interaction effects (Sekiguchi et al. 2015; Foucart et al. 2015; Radice et al. 2016).”