Core-collapse supernova explosions triggered by a quark-hadron phase transition during the early post-bounce phase

TL;DR

This paper investigates how a quark-hadron phase transition during the early post-bounce phase of core-collapse supernovae can trigger explosions, leading to observable neutrino bursts and potential heavy element synthesis.

Contribution

It introduces a new supernova explosion mechanism driven by a quark-hadron phase transition using a novel hybrid equation of state in detailed simulations.

Findings

Quark-hadron phase transition induces supernova explosions.

Neutrino burst signals core structural changes.

Ejected matter is neutron-rich, suitable for r-process nucleosynthesis.

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 vp-process might occur.