A statistical model for a complete supernova equation of state

By M. Hempel, J. Schaffner-Bielich. 2009

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Abstract A statistical model for the equation of state and the composition of supernova matter is presented. It consists of an ensemble of nuclei and interacting nucleons in nuclear statistical equilibrium. A relativistic mean field model is applied for the nucleons. The masses of the nuclei are taken from experimental data and from nuclear structure calculations. Excluded volume effects are implemented in a thermodynamic consistent way so that the transition to uniform nuclear matter can be described. Thus the model can be applied at all densities relevant for supernova simulations, i.e. ρ = 10 5 – 10 15 g / cm 3 , and it is possible to calculate a complete supernova equation of state table. The importance of the nuclear distributions for the composition is shown and the role of shell effects is investigated. We find a significant contribution of light clusters which is only poorly represented by α-particles alone. The equation of state is systematically compared to two commonly used models for supernova matter which are based on the single nucleus approximation. In general only small differences are found. These are most pronounced around the (low-density) liquid–gas phase transition line where the distribution of light and intermediate clusters has an important effect.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/e72e09c30001ce714e764eee1b8d41fdc5e10098

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Citations in the corpus

Neutron-powered precursors of kilonovae (2014, methodology): “This calculation was performed by using a nuclear reaction network to post-process SPH trajectories extracted from the 1.35-1.35M⊙ NS binary merger simulation of Bauswein et al. (2013) that employed the DD2 equation of state (Typel et al. 2010; Hempel & Schaffner-Bielich 2010).”
Gravitational waves and non-axisymmetric oscillation modes in mergers of compact object binaries (2011, background): “Though to date several finite-temperature EOSs (Typel et al. 2010; Hempel & Schaffner-Bielich 2010; Shen etal.”
Multiple physical elements to determine the gravitational-wave signatures of core-collapse supernovae (2011, background): “so worth mentioning that a rush of nice work to this end has been reported recently including new schemes towards the GR radiation-hydrodynamic simulations [92, 93, 94] and new sets of supernova EOSs [95, 96, 97]. 13 In this sense, these two approaches are complimentary in understanding the GW signa”
Binary Neutron Star Mergers: Mass Ejection, Electromagnetic Counterparts, and Nucleosynthesis (2018, methodology): “For instance, due to the appearance of Λ hyperons after the merger, the BHBΛf EOS predicts more violent mergers and brighter radio flares by up to two orders of magnitude compared with the DD2 EOS, from which it only differs at high densities due to the inclusion of hyperons.”
GW170817: Joint Constraint on the Neutron Star Equation of State from Multimessenger Observations (2017, methodology): “Bauswein et al. (2017) combined this observation with empirical relations between NS radii and the threshold mass for prompt collapse, which was previously found by means of simulations with an approximate treatment of general relativity (GR; Bauswein et al. 2013a), to tentatively rule out EOSs pred”
Comprehensive nucleosynthesis analysis for ejecta of compact binary mergers (2014, background): “The employed microphysical EOSs are SFHO, SFHX (Steiner, Hempel & Fischer 2013), TM1 (Sugahara & Toki 1994; Hempel et al. 2012), TMA (Toki et al. 1995; Hempel et al. 2012), and DD2 (Hempel & Schaffner-Bielich 2010; Typel et al. 2010), which are all derived within the relativistic mean-field approach”
Unified equation of state for neutron stars on a microscopic basis (2015, unknown): “Also recently, a complete EoS for supernova matter has been developed within the statistical model (Hempel & Schaffner-Bielich 2010).”
NEW EQUATIONS OF STATE IN SIMULATIONS OF CORE-COLLAPSE SUPERNOVAE (2011, methodology): “It is the same analytic expression as in the original reference of the HS model (Hempel & Schaffner-Bielich 2010) and used previously by Ishizuka et al. (2003), but now we consider only excitation energies below the binding energy of the corresponding nucleus, in order to represent that the excited…”
Improved axion emissivity from a supernova via nucleon-nucleon bremsstrahlung (2019, background): “ 1] 1 ; (5.2) with inverse temperature = 1=T and chemical potential N. Commonly used modern equations of state for supernova studies consider the strongly interacting nucleons at the mean eld level [49,70], which are based on the single-particle self energy that can be separated into scalar (S) and”
The Nuclear Symmetry Energy (2016, background): “[127] introduces a statistical ensemble of nuclei in the low density part together with a relativistic mean field for nucleons and alpha particles, as well as for the homogeneous matter.”