Planetary Nebulae as Probes of Stellar Evolution and Populations

Letizia Stanghellini

Understanding asymptotic giant branch (AGB) envelope ejection and planetary nebula (PN) evolution is essential in astrophysics, since low- and intermediate-mass stars and their ejecta are excellent probes of stellar populations in galaxies, and have been detected in all types of galaxies and in the intra-cluster space. Stars in this mass range constitute a major component (by mass) of the stellar material in the Universe, and thus a correct understanding of their evolution in different environments has the potential to advance many astrophysical fields. Furthermore, these stars play a fundamental role in cosmic recycling, being major contributors to the carbon and nitrogen abundances for the next generation of stars. In this talk I will show the latest results on Magellanic Cloud PNe, including data acquired with HST and Spitzer. Magellanic Cloud PNe are important both because their distances are well known -- while this is not true for most Galactic PNe -- and because they extend the metallicity baseline for AGB and PN studies.