Nuestro objetivo es mejorar los analisis espectroscopicos para intentar obtener la descripcion mas realista posible de las atmosferas de las estrellas OB de la Galaxia. De esta manera podremos responder a ciertas preguntas que esten abiertas hoy en dia sobre estos objetos, en especial a si la discrepancia de He se puede explicar via procesos de

From an analysis of the stars remaining in central regions of the Galaxy after subtracting those belonging to the disc and the bulge, we deduce that the inner bulge must have an extra young population with respect to the rest of the bulge. It is shown that there is a higher ratio of very bright stars in the central bulge than there is in the outer

A most desirable feature of a standard candle to estimate astronomical distances is robustness against changes in metallicity and age. It is argued that the radii of main-sequence stars with spectral types from solar to A0 show predictable changes with metallicity and detectable changes with evolution. Such stars populate the solar neighborhood and

Many barred galaxies show enhanced star formation activity in ring-like regions around their centres, at typical radii of 1-2 kpc. We show how kinematic (WHT TAURUS Fabry-Pérot velocity mapping) and imaging (CFHT near infrared adaptive optics) observational tests, combined with dynamical modelling, can help in unravelling the dynamics and star

Recent data colleted by the helioseismic experiments aboard SOHO have allowed the detection of low degree p-modes with lower and lower order, n. In particular, the GOLF experiment is currently able to identify unambiguously modes as low as n = 8 for l = 0, and l = 1 (e.g., ≍1.3 mHz). To detect p-modes with lower n (hence lower frequeny), where the

The study of δ Scuti stars in a cluster allows to consider that all the objects have the same age, chemical composition and distance. In addition to this, the parameters like metallicity or distance are better estimated for stars belonging to a cluster than for typical field stars. We consider here a set of four Delta Scuti stars in the Pleiades