Formation of quark phases in protoneutron stars: the transition from the 2SC to the normal quark phase

TL;DR

This paper investigates the phase transition processes in protoneutron stars, focusing on the formation of quark matter and the transition from the 2SC phase to the normal quark phase during deleptonization.

Contribution

It provides a detailed analysis of the phase transition dynamics between nucleonic matter, 2SC, and normal quark phases in protoneutron stars, including neutrino diffusion effects.

Findings

Unpairing transition occurs at low lepton fractions.

Deleptonization triggers phase transition in intermediate-mass stars.

Less massive stars only form the normal quark phase after deleptonization.

Abstract

We study the process of formation of quark phases in protoneutron stars. After calculating the phase transition between nucleonic matter and the 2SC phase at fixed entropy and lepton fraction, we show that an unpairing transition between the 2SC phase and the normal quark phase occurs for low lepton fractions. We then calculate the process of diffusion of neutrinos in protoneutron stars and show that for intermediate values of the mass of the star, the deleptonization triggers the phase transition between the two quark phases after a temporal delay of a few seconds. In less massive stars instead only the normal quark phase is formed at the end of the deleptonization stage. We also discuss the possible astrophysical implications of our scenario.