Planetary Nebulae as Probes of Stellar Evolution and Populations

Planetary Nebulae (PNe) have been used satisfactory to test the effects of stellar evolution on the Galactic chemical environment. Moreover, a link exists between nebular morphology and stellar populations and evolution. We present the latest results on Galactic PN morphology, and an extension to a distance unbiased and homogeneous sample of Large Magellanic Cloud PNe. We show that PNe and their morphology may be successfully used as probes of stellar evolution and populations. 1. Relevance of Planetary Nebulae Planetary Nebulae represent the fate of most stars of masses in the range 1–10 M⊙. The effects and consequences of their evolution are of great importance in stellar population studies, since PNe represent the progeny of the most common stars in galaxies. PNe have been observed for centuries in the Galaxy, and more recently in other galaxies such as the Magellanic Clouds, and between galaxies. They have been identified as far as in the Virgo group. Planetary Nebulae studied in different galaxies are of exceptional interest to probe stellar populations in a variety of environments. These studies would also allow the direct comparison of similar stellar populations in the different host galaxies (see also Maciel, this volume). The ejection of the stellar envelopes of Asymptotic Giant Branch (AGB) stars yields to the PN formation, and also marks the beginning of the cosmical recycling process. In fact, PNe are among the most important cosmic sources of carbon and other elements whose abundance is modified in the