Core-Collapse Supernova Explosions Triggered by a Quark-Hadron Phase Transition During the Early Post-Bounce Phase

Abstract

We explore explosions of massive stars, which are triggered via the quark-hadron phase transition during the early post bounce phase of core-collapse supernovae. We construct a quark equation of state, based on the bag model for strange quark matter. The transition between the hadronic and the quark phases is constructed applying Gibbs conditions. The resulting quark-hadron hybrid equations of state are used in core-collapse supernova simulations, based on general relativistic radiation hydrodynamics and three flavor Boltzmann neutrino transport in spherical symmetry. The formation of a mixed phase reduces the adiabatic index, which induces the gravitational collapse of the central protoneutron star. The collapse halts in the pure quark phase, where the adiabatic index increases. A strong accretion shock forms, which propagates towards the protoneutron star surface. Due to the density decrease of several orders of magnitude, the accretion shock turns into a dynamic shock with matter outflow. This moment defines the onset of the explosion in supernova models that allow for a quark-hadron phase transition, where otherwise no explosions could be obtained. The shock propagation across the neutrinospheres releases a burst of neutrinos. This serves as a strong observable identification for the structural reconfiguration of the stellar core. The ejected matter expands on a short timescale and remains neutron-rich. These conditions might be suitable for the production of heavy elements via the r-process. The neutron-rich material is followed by proton-rich neutrino-driven ejecta in the later cooling phase of the protoneutron star where the νp-process might occur.

A new quark-hadron hybrid equation of state for astrophysics

“…Pons et al 2001;Popov et al 2006;Blaschke et al 2013b) and simulations of core-collapse supernovae (cf. Sagert et al 2009;Fischer et al 2011;Nakazato et al 2014). It is therefore of paramount interest to develop quark-hadron hybrid models from which it is possible to deduce observables that allow us to further constrain the as yet highly uncertain QCD phase diagram, e.g.…”

Simultaneous Chiral Symmetry Restoration and Deconfinement Consequences for the QCD Phase Diagram

“…Nakazato et al 2008;Sagert et al 2009;Fischer et al 2011). Such a transition is expected at high baryon densities, > n n B S , in the core of a newly born protoneutron star.…”

“…Specifically, we choose the parametrization DD2 from Typel et al (2010). We aim to make vBag accessible to a broader spectrum of astrophysics applications where the appearance of quark matter can be studied, e.g., simulations of neutron star mergers, core-collapse supernovae, and protoneutron star cooling (cf., Pons et al 2001;Nakazato et al 2008;Sagert et al 2009;Fischer et al 2011).…”

Delta isobars in neutron stars

“…Remarkably, the velocity of conversion is so high that in many studies, including detailed three-dimensional numerical simulations [52], almost the whole hadronic star is converted within a few milliseconds. Moreover, since the energy released in such a process is of the order of 10 52 erg, it is clear that a similar event would provide very strong neutrino and electromagnetic signals, possibly connected with supernovae and gamma-ray-bursts [40,42,[53][54][55]. An interesting outcome of Refs.…”