Neutrino and Electron-positron Pair Emission from Phase-induced Collapse of Neutron Stars to Quark Stars

TL;DR

This paper models the phase-induced collapse of neutron stars into quark stars, revealing intense neutrino and pair emissions that could explain short gamma-ray bursts.

Contribution

It introduces a Newtonian hydrodynamic simulation of neutron star collapse with phase transition, highlighting oscillations and emissions not previously detailed.

Findings

Oscillations in neutrinosphere temperature and density occur out of phase.

Intense pulsating neutrino and antineutrino fluxes are emitted.

Ejected mass can be accelerated to relativistic speeds, potentially causing gamma-ray bursts.

Abstract

We study the energy released from phase-transition induced collapse of neutron stars, which results in large amplitude stellar oscillations. To model this process we use a Newtonian hydrodynamic code, with a high resolution shock-capturing scheme. The physical process considered is a sudden phase transition from normal nuclear matter to a mixed phase of quark and nuclear matter. We show that both the temperature and the density at the neutrinosphere oscillate with time. However, they are nearly 180 degree out of phase. Consequently, extremely intense, pulsating neutrino/antineutrino and leptonic pair fluxes will be emitted. During this stage several mass ejecta can be ejected from the stellar surface by the neutrinos and antineutrinos. These ejecta can be further accelerated to relativistic speeds by the electron/positron pairs, created by the neutrino and antineutrino annihilation outside the stellar surface. We suggest that this process may be a possible mechanism for short Gamma-Ray Bursts.