Effects of Stellar-Mass and the ISM on the Evolving Morphologies of Planetary Nebulae

Abstract

A significant step forward in the understanding of Planetary Nebula (PN) formation can be achieved by exploring the connection of PN with stellar evolution. In particular, the initial mass of the star plays a crucial role, as it determines the evolutionary timescales, the density structure of the gas and the amount of energy injected into the nebula. Here we summarize our study of the effects of stellar mass in PN formation. Our numerical simulations include the evolution of the stellar wind for different initial progenitor masses and the influence of the ISM. We also investigate how the systemic velocity of the star with respect to its surrounding medium affects the PN formation. We find that unless the star is moving, most of the mass lost by PN progenitors can be found in the low surface brightness extended halos, where the stellar ejecta is mixed with ISM material. For a moving central star, the interaction with the ISM considerably reduces the mass of the circumstellar envelope during the AGB and PN phases owing to ram pressure stripping.