Protoneutron Star Properties via Gravitational Wave Asteroseismology

Abstract

We examine the f -and p 1 -modes of gravitational waves from the protoneutron stars formed just after the core bounce of core-collapse supernovae. As a result, we find that the frequencies of fand p 1 -modes are almost independent of the choice of the radial distribution of the electron fraction and entropy per baryon. We also find that the frequencies of the f -and p 1 -modes can be expressed well the average density of protoneutron stars. In particular, we are successful to derive the universal relation between the frequencies and the square root of the average density independently of the equation of state. Since the dependence on the stellar properties is different from that for the known gmode frequencies, one can determine the mass and radius of protoneutron star via careful observation of the gravitational wave variation.