En esta tesis se ha llevado a cabo el estudio de abundancias químicas de las estrellas secundarias en sistemas binarios de rayos X de masa pequeña con el fin de extraer información sobre la nucleosíntesis en estrellas masivas y los procesos de formación de objetos compactos, tanto agujeros negros como estrellas de neutrones . Las estrellas

We review the needs of the CoRoT /exoplanet program in terms of complementary observations. Such observations are indeed an essential element of the science of the CoRoT mission at different levels: prior to the launch for a characterization and a careful selection of the target stars in the exoplanet fields and during or after the CoRoT flight

The standard ΛCDM model predicts that the major merger rate of galaxy-size dark matter halos rises rapidly with redshift. The average number of close companions per galaxy, Nc, is often used to infer the galaxy merger rate; however, recent observational studies suggest that Nc evolves very little with redshift. Here we use a ``hybrid'' N-body

Aims.We used the UVES spectrograph (VLT-UT2 telescope) to obtain high-resolution spectra of 6 stars hosting transiting planets, namely for OGLE-TR-10, 56, 111, 113, 132, and TrES-1. These spectra are now used to derive and discuss the chemical abundances for C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, and Zn. Methods: .Abundances

The GAW project aims to test the feasibility of a new generation of Imaging Atmospheric Cherenkov Telescopes that join high flux sensitivity with Large Field of View capability. It consists of an array of 3 imaging Cherenkov telescopes each equipped with a Fresnel refractive lens of about 3.6 m2 geometrical area and an array of multi-anode

En esta tesis doctoral se realiza un estudio de las propiedades magnéticas del Sol en calma, aquellas regiones en el Sol donde el magnetismo pasa casi desapercibido. Se llega a la conclusión que los campos magnéticos son débiles, de unas pocas centenas de Gauss, llenando una porción pequeña del elemento de resolución. Además las estructuras