En esta tesis presentamos el primer estudio homogéneo y uniforme de abundancias químicas en un amplio conjunto de estrellas con planetas y en una muestra de comparación de estrellas sin planetas detectados. Se analizaron las abundancias químicas de 19 metales, y no se encontraron diferencias significativas . Se confirma que el exceso de hierro se

We present new near-infrared (J and K) magnitudes for 114 RR Lyrae stars in the globular cluster ω Centauri (NGC 5139), which we combine with data from the literature to construct a sample of 180 RR Lyrae stars with J and K mean magnitudes on a common photometric system. This is currently the largest such sample in any stellar system. We also

As part of the Dwarf galaxies Abundances and Radial-velocities Team (DART) program, we have measured the metallicities of a large sample of stars in four nearby dwarf spheroidal galaxies (dSph's): Sculptor, Sextans, Fornax, and Carina. The low mean metal abundances and the presence of very old stellar populations in these galaxies have supported

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Context: .Statistical properties of H ii region populations in disk galaxies yield important clues to the physics of massive star formation. Aims: .We present a set of H ii region catalogues and luminosity functions for a sample of 56 spiral galaxies in order to derive the most general form of their luminosity function. Methods: .H ii region

The limited angular resolution of γ-ray telescopes prevents a direct identification of the majority of sources detected so far. This is particularly true for the low latitude, probably galactic, ones only 10% of which has been identified. Most counterparts of the identified low-latitude γ-ray sources are Isolated Neutron Stars (INS), both radio