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

Investigating the reliability of the assumption of instantaneous chemical equilibrium (ICE) for calculating the CO number density in the solar atmosphere is of crucial importance for the resolution of the long-standing controversy over the existence of ``cool clouds'' in the chromosphere and for determining whether the cool gas owes its existence

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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

(4) Vesta is the unique large asteroid with a basaltic surface present in the Asteroid Belt. In recent years, several smaller asteroids having similar composition have been discovered in the neighbourhood of Vesta and even far away from it. It has been suggested that all these small asteroids came from Vesta even if dynamical studies do not fully

Observed variations of the magnetic field strength in sunspot umbrae consist of intrinsic oscillations and ``false'' oscillations due to time-dependent opacity effects. Here we present an approach intended for the separation of these components. We develop a mathematical formalism based on the analytical solution of the MHD equations including