In addition to optical photometry of unprecedented quality, the Sloan Digital Sky Survey (SDSS) is also producing a massive spectroscopic database. We discuss determination of stellar parameters, such as effective temperature, gravity and metallicity from SDSS spectra, describe correlations between kinematics and metallicity, and study their

We have recently (Gonçalves et al. 2006) shown that previously reported enhanced N abundances in fast, low-ionization emission regions (FLIERs) of PNe, particularly in NGC 7009, may be due to ionization effects. We reached this conclusion through the 3D MOCASSIN photoionization modeling of the bright inner rim of NGC 7009 and its pair of FLIERs

We present preliminary results from an Open Clusters Polarimetric Survey which is being developed at La Plata Observatory (Argentina). The aim of this Survey is to provide clues about the characteristics of the dust responsible for extinction and polarization in the light from member stars of Open Clusters, about its galactic distribution and also

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In this work, we study the gravitational influence of the material extending from Uranus orbit to the Kuiper belt and beyond on objects moving within these regions. We conclude that a density distribution given by ρ (r)=(1)/(r) (for r >= 20 AU) generates a constant acceleration towards the Sun on those objects, which, with the proper amount of mass