DUST FORMATION IN WINDS OF LONG-PERIOD VARIABLES .3. DYNAMICAL MODELSAND CONFIRMATION OF A DUST-INDUCED KAPPA-MECHANISM

We present self-consistent dynamical models for purely dust driven win ds of C-rich AGE stars which are based on the coupled system of radiat ion hydrodynamics and time-dependent dust formation and growth. Invest igating the dependence of the solution on the relative abundance of ca rbon to oxygen (i.e. the amount of condensable material) for several s ets of stellar parameters we obtain stationary dust driven winds as we ll as solutions with periodic dust formation and creation of shock wav es without applying a variable inner boundary to simulate a pulsation of the underlying star. Model series with certain stellar parameters s how a transition from stationary winds to time-dependent solutions wit h discrete dust layers and shock waves as the carbon/oxygen abundance ratio exceeds a critical value. Summarizing the results, our calculati ons demonstrate that the limit case of stationary dust driven winds ca n be reproduced using the full, time-dependent code and furthermore pr ovide an independent confirmation of the dust-induced kappa-mechanism proposed by Fleischer et al. (1994).