In this paper, we explore the properties of hot neutron star matter and (proto-) neutron stars at finite temperatures and entropies. We also determine the particle compositions of (proto-) neutron star matter as well as the stellar structure for three different parameterizations related to these mysterious supernova remnants. After a star has exhausted its resources, the fusion process comes to an end, and it can no longer support its mass against the force of gravity. Once the star explodes, it gives birth to a short-lived (proto-) neutron star, which depending on its final mass can turn in to a black hole or neutron star. We adopt a density dependent relativistic mean-field approach to solve the many body equations and to determine models for the equation of state of dense stellar matter. The relativistic Green function formalism is used to formulate expressions which describe the properties of such matter. All particles of the baryon octet have been included in the calculations along with all electrically charged states of the ∆(1232) isobar.