In this paper, we present a study of the abundances of Si, Ca, Sc, Ti, V, Cr, Mn, Co, and Ni in a large set of stars known to harbor giant planets, as well as in a comparison sample of stars not known to have any planetary-mass companions. We have checked for possible chemical differences between planet hosts and field stars without known planets

We discuss the possibility that the extended structures, lacking young stars, routinely found in dwarf irregular galaxies (dIrr) are a consequence of a progressive shrinking of the star forming region. This would be an alternative scenario to the possible halo-disk structure of dIrr. Although the final answer must wait until kinematical data of

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En la tesis se presentan los resultados de un estudio comparativo de la formación estelar que tiene lugar en dos galaxias espirales distintas: una floculenta (NGC 4395) y una de gran diseño (NGC 5457). Para ello se obtuvo una serie de imágenes en banda estrecha en diferentes líneas de emisión de las regiones HII. De esta forma no sólo se obtuvo

The theoretical understanding of the linear standing or propagating magnetohydrodynamic waves in a variety of solar coronal structures is far from complete since analytical solutions to the linearised MHD equations can only be found for very simple magnetic configurations. In this paper, we use a numerical code to solve the linear fast and Alfvén

We present the results of our near-infrared spectroscopic program of Trans-Neptunian objects (TNOs), Centaurs and comet nuclei. TNOs, centaurs, and Jupiter family (JF) comets are three intimately related populations of minor planet bodies originated in the outer solar system. They probably contain some of the least modified materials remaining from