THE DYNAMIC EVOLUTION OF THE SHELL NEBULAE BY USING INTERACTING WIND MODEL

Planetary Nebulae (PN) are astronomical objects made up primarily of gaseous materials. A planetary nebulae are an emission nebulae consisting of an expanding glowing shell of ionized gas ejected during the Asymptotic Giant Branch (AGB) phase. of certain types of stars late in their life. late in their life,[1]. This name originated with their first discovery in the 18th because of their similarity in appearance to giant planets when viewed through small optical telescopes, and is otherwise unrelated to the planets of the solar system,[2]. The importance of winds from central stars of PN in preventing material backfill was recognized as early as 1966 by Mathews (1966),[3 ]. The resents IUE observations have shown that winds from central stars are much more common than previously thought. Heap (1982) was the first suggested that central stars with a luminosity to mass ratio 11,000 will have wind. Combining this empirical criterion with the Pycznski core mass-luminosity relationship, we have lower central star mass limit of ~0.65Mo,[4].The wind velocities can be accurately measured and have been found to range from 2000-8000 km/s. central stars with higher temperatures are also suspected to generate higher velocity winds. It is easy to show that such high velocity winds carry a significant amounts of momentum and energy and should have an important effect on the dynamical evolution of PN. Fig (1) shows the formation phases of planetary nebulae on HR Diagram.