Dynamical effects of winds and radiation on the structure of the planetary nebulae

Detailed numerical solutions of the equations of conservation of mass, momentum, and energy have been obtained for model planetary nebulae, each featuring a fast wind (v(f) similar or equal to 10(8) cm s(-1)) from the central star ploughing into the previously ejected envelope of the star. The envelope is assumed to have been ejected as a slow wind (v(s) similar or equal to 10(6) cm s(-1)) over a period of about 1000 years. The pressure is assumed to be constant in a region bounded on the inside by a shock front separating freely flowing fast-wind gas and shocked fast-wind gas and on the outside by a shock front separating undisturbed slow-wind gas and shocked slow-wind gas. In this region, dynamical pressure is negligible. The results have been applied to 13 nebulae for which fast-wind velocities, ionized masses, and mass transfer rates have been obtained. In most cases, the outer structure of the nebula and the overall dynamics are affected little by the fast wind. However, the inner structure and high temperature radiation are definitely affected by the fast wind.