DYNAMICAL MODELS OF ATMOSPHERES OF LONG-PERIOD VARIABLES - A COMPARATIVE-STUDY

Numerical models for atmospheres of carbon-rich long-period variables (LPVs) obtained by two different codes are compared with regard to the radial structure of the circumstellar shell, its dynamics and the pro pagation of shock waves, the dust formation and its effects on the dyn amics and thermodynamics of the atmosphere as well as the mass loss ra tes and the outflow velocities. The general features of the models suc h as the formation of discrete dust layers, the occurrence of multiper iodicity or the dust-induced IE-mechanism in purely dust-driven winds are the same in both cases while a detailed quantitative comparison of special model calculations demonstrates certain effects caused by the different numerical schemes. Nevertheless we find that the two modell ing methods give remarkably similar results with respect to the comple x physical system under consideration.