Neutrino-driven Winds from Young, Hot Neutron Stars

Questions raised by the study of Salpeter and Shapiro (1981) of neutrino and photon emission from a young, hot neutron star are addressed. The general coupled hydrodynamical-radiative transport equations for this emission are presented, and it is shown how these equations reduce to those of Salpeter and Shapiro in the plane-parallel, hydrostatic limit. It is demonstrated that the photon flux cannot be reduced to sub-Eddington levels by discarding the plane-parallel limit and allowing a static atmosphere to 'puff out' to large radius or even by including convective energy transport. This emphasizes the need for dynamical outflow solutions, which are determined numerically. Simple analytic scaling laws which approximate the numerical results are derived.