Stellar neutrino energy loss rates due toMg24suitable forO+Ne+Mgcore simulations

Abstract

Neutrino losses from proto-neutron stars play a pivotal role to decide if these stars would be crushed into black holes or explode as supernovae. Recent observations of subluminous Type II-P supernovae (e.g., 2005cs, 2003gd, 1999br, 1997D) were able to rejuvenate the interest in 8-10 M$_{\odot}$ stars which develop O+Ne+Mg cores. Simulation results of O+Ne+Mg cores show varying results in converting the collapse into an explosion. The neutrino energy loss rates are important input parameters in core collapse simulations. Proton-neutron quasi-particle random phase approximation (pn-QRPA) theory has been used for calculation of neutrino energy loss rates due to $^{24}$Mg in stellar matter. The rates are presented on a detailed density-temperature grid suitable for simulation purposes. The calculated neutrino energy loss rates are enhanced up to more than one order of magnitude compared to the shell model calculations and favor a lower entropy for the core of these massive stars.