Planetary nebulae (PNe) in the Magellanic Clouds (LMC, SMC) offer a unique opportunity to study both the population and evolution of low- and intermediate-mass stars in an environment which is free of the distance scale bias that hinders Galactic PN studies. The emission shown by PNe in the 5-40 μm range is characterized by the presence of a

In this paper we explore the dynamics of ionization bounded planetary nebulae after the termination of the fast stellar wind. When the stellar wind becomes negligible, the hot, shocked bubble depressurizes and the thermal pressure of the photo-ionized region, at the inner edge of the swept-up shell, becomes dominant. At this stage the shell tends

We present preliminary conclusions derived from the analysis of a sample of galactic PNe with [WC]-type central stars (WCPNe) observed with Spitzer/IRS. We report the detection of double-dust (C-rich and O-rich) chemistry in all stars in the sample for which a good S/N spectrum was obtained. Our observations reveal that the simultaneous presence of

Not Available

The preliminary results of the chemical analysis of a sample of 22 galactic R-stars with measured parallaxes are presented. We have derived the C/O and 12C/13C ratios, the average metallicity ([M/H]) and the Li abundances. We find that most of the stars have 12C/13C below ˜ 20 with no significant difference between cool and hot R-stars. The C/O

Recent cosmological N-body simulations suggest that current empirical estimates of tidal radii in dSphs might be underestimated by at least one order of magnitude. To constrain the plausibility of this theoretical framework, we undertook a multiband (U,B,V,I) survey of the Carina dSph. Deep B,V data of several fields located at radial distances