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

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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

This proposal is a resubmission of an accepted RXTE AO 10 proposal. Our aim is to test evolutionary and type I burst models with the observed type I X-ray burst behaviour of the bright ultra-compact binary system 4U 1820-30. The short orbital period suggests that the companion white dwarf is hydrogen deficient, with evolutionary models predicting a

As a main example for the superstatistics approach, we study a Brownian particle moving in a d-dimensional inhomogeneous environment with macroscopic temperature fluctuations. We discuss the average occupation time of the particle in spatial cells with a given temperature. The Fokker-Planck equation for this problem becomes a stochastic partial