Structure of protoneutron stars within a static approach

Abstract

To investigate the stability of the protoneutron stars in their early evolution, the minimum gravitational mass plays a fundamental role. This quantity depends upon the temperature profile assumed. We study within a static approach the stability of a protoneutron star. In particular we focus on a suitable temperature profile suggested by dynamical calculations. We consider a protoneutron star as composed of an isothermal core and an isentropic outer part. To describe physical properties of the interior we employ a microscopically derived equation of state for nuclear matter. For the outer part we employ the Lattimer-Swesty equation of state. The global structure is studied. The assumed temperature profile turns out to give a range of stability which supports temperature values in line with those coming from dynamical calculations. The maximum mass instead depends only upon the equation of state employed.