A COUPLED HYDRODYNAMIC-IONIZATION MODEL FOR THE CLUMPY WOLF-RAYET RING NEBULA RCW-58

We present a time-dependent hydrodynamic model for the Wolf-Rayet ring nebula RCW 58 that includes a self-consistent treatment of the nonequ ilibrium evolution of the ionisation state of the gas. We investigate the feasibility that hydrodynamic ablation from embedded dense clumps in the nebula is responsible for the high-velocity ultraviolet absorpt ion features observed towards the central star. It is found that the o bserved correlation between the velocity of these features and the ion isation potential of the absorbing ion can be qualitatively reproduced by such a model. The calculated velocity range depends strongly on th e adopted wind velocity.