Dynamical models of LPV atmospheres: 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 propagation of shock waves, the dust formation and its effects on the dynamics and thermodynamics of the atmosphere as well as the mass loss rates and the outflow velocities. The general features of the models such as the formation of discrete dust layers, the occurrence of multiperiodicity or the dust-induced -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 modelling methods give remarkably similar results with respect to the complex physical system under consideration.