Pair luminosity and cooling of newborn strange star: Color-flavor-locked and two-flavor color superconducting quarks

Abstract

Following the previous wor k[1] here we consider early thermal evolution of hot strange stars made of color superconducting quarks in two different pairing states: two-flavor color superconductor (2SC) and color-flavor-locked (CFL) phases, taking into account cooling by neutrinos and electron-positron pair creation due to the Schwinger process. We show that Schwinger luminosity in the electrosphere is a universal function of temperature, independent of quark matter phase for quark chemical potential $\mu_q>280$ MeV. The surface of a strange star in all the cases cools faster than its interior. This leads to a fast decrease of pair luminosity with time, so that it does not exceed $10^{46}$ erg/s at 1 second after strange star formation. Neutrino luminosity dominates over pair luminosity in all the cases except for the CFL phase with a large gap parameter $\Delta>60$ MeV, where there is a strong suppression of neutrino emission. The total energy emitted in electron-positron pairs is always smaller than the energy emitted in neutrinos, but they become comparable for the large gap parameter.