SwiftObservations of the 2006 Outburst of the Recurrent Nova RS Ophiuchi. II. One‐dimensional Hydrodynamical Models of Wind‐driven Shocks

Abstract

Following the early Swift X-ray observations of the latest outburst of the recurrent nova RS Ophiuchi in 2006 February (Paper I), we present new one-dimensional hydrodynamical models of the system that take into account all three phases of the remnant evolution. The models suggest a novel way of modeling the system by treating the outburst as a sudden increase followed by a decrease in wind mass-loss rate and velocity. The differences between this wind model and previous Primakoff-type simulations are described. A more complex structure, even in one-dimension, is revealed through the presence of both forward and reverse shocks, with a separating contact discontinuity. The effects of radiative cooling are investigated, and key outburst parameters such as mass-loss rate and ejecta velocity and mass are varied. The shock velocities as a function of time are compared to the ones derived in Paper I. We show how the manner in which the matter is ejected controls the evolution of the shock and that for a well-cooled remnant, the shock deceleration rate depends on the amount of energy that is radiated away.