Energy release due to antineutrino untrapping from hot quark stars

An equation of state for 2-flavor quark matter (QM) with diquark condensation under the conditions for compact stars -$\beta$-equilibrium, charge and color neutrality- is presented. Trapped antineutrinos prevent the formation of the diquark condensate at moderate densities above a critical value of the antineutrino chemical potential ${\mu }_{{\bar{\nu }}_e}^c$. The following consequences are presented: 1) The star develops a 2-phase structure (${\mu }_{{\bar{\nu }}_e}\ge {\mu }_{{\bar{\nu }}_e}^c$): a color superconducting QM core and a normal QM shell. 2)During the cooling, when the temperature is small enough ($T<1$ MeV) the antineutrino mean free path becomes larger than the thickness of the normal QM shell and the antineutrinos get untrapped in a sudden burst. The energy release is estimated as $\simeq {10}^{52}$ erg and an antineutrino pulse is expected to be observed.