Context: Interpretation of linearly polarized parameters of the lines of complex atoms for the second solar spectrum needs a lot of collisional coefficients which are often poorly known. Aims: We provide general and simple formulae giving the coefficients of the atomic master equation (depolarization, polarization transfer, population transfer, and

In this paper, we present a thorough study of the T Tauri system MO Lup. We report on its previously unrecognized triple spectroscopic nature. Our study is mainly based on high-resolution spectroscopic monitoring. The elements of the spectroscopic orbits are derived from a detailed analysis of radial velocity data for the short-period spectroscopic

The influence of microlensing on the profiles of emission lines generated in a biconical geometry is discussed. Microlensing amplification in this anisotropic model is not directly related to the bicone's intrinsic size but, rather, depends on the orientation of the bicone axis and on the cone aperture. The orientation of the projected bicone with

En este trabajo hemos estudiado la luz difusa en cúmulos y grupos de galaxias. La luz difusa está compuesta por estrellas desligadas de las galaxias del cúmulo y que se mueven bajo la acción del potencial global del cúmulo. Esta componente cúmular corresponde a un 5-15% de la masa total del cúmulo. Fue descubierta por primera vez en el cúmulo de

As part of a major program to use isolated Local Group dwarf galaxies as near-field probes of cosmology, we have obtained deep images of the dwarf irregular galaxy Leo A with the Advanced Camera for Surveys aboard the Hubble Space Telescope. From these images we have constructed a color-magnitude diagram (CMD) reaching apparent [absolute]

Aims:We investigate the dynamics of the nebula around the symbiotic star Hen 2-147, determine its expansion parallax, and compare it with the distance obtained via the period-luminosity relation for its Mira variable. Methods: A combination of multi-epoch HST images and VLT integral field high-resolution spectroscopy is used to study the nebular