Accreting black holes and neutron stars release an unknown fraction of the infalling particles and energy in the form of collimated jets. The jets themselves are radiatively inefficient, but their power can be constrained by observing their interaction with the surrounding environment. Here we present observations of X-ray binary jet-ISM

We have derived beryllium abundances for all Li-rich giant stars known in the literature and visible from the southern hemisphere and 10 other Li-normal giants, aimed to investigate the origin of the Lithium in the Li-rich giants. In particular, we test the predictions of the engulfment scenario proposed by Siess & Livio (1999) where the engulfment

The He I triplet at 10830 Å has a great potential for determining the magnetic field vector in the upper chromosphere. The triplet is Zeeman sensitive (Landé factors 2.0, 1.75 and 1.25) and shows the signature of the Hanle effect under appropriate conditions. Additionally, the Zeeman sublevels are influenced by the Paschen-Back effect leading to

We present the results of an on-going program for the identification and characterization of optical counterparts of Ultra-Luminous X-ray (ULX) sources. The targets have been selected from the catalogues by Colbert & Ptak (2002) and Swartz et al. (2004). A clear identification based on unambiguous optical spectral features was possible for 26

Planetary Nebula (PN) shells and AGB circumstellar envelopes evolve under a wide range of external conditions, from the high ISM densities found in the Galactic plane, to the rarefied and hot intracluster medium where the systemic velocity of the star can be as high as 2000 km s-1. We explore the effects that the external pressure and/or stellar

We use UVES spectroscopy of PB 6 to study the variation of its physical conditions as a function of position including: temperature, density, chemical composition and velocity. We present preliminary results from this work. In particular we want to find the relevance of the contribution of the wind from the central star to the chemical composition