We present an IZ photometric survey covering a total area of about 1000 arcmin2 around the ɛ Orionis young massive star (˜10 Myr, d=412 pc) and reaching a limiting magnitude I=22. From the resulting I, I-Z color-magnitude diagram we have selected 123 red candidates in the interval I=15--22 mag, which according to evolutionary models corresponds to

With the goal of confirming the metallicity ``excess'' observed in stars with planetary mass companions, we have conducted a high-precision spectroscopic study of a ``comparison'' sample of dwarfs included in the CORALIE extra-solar planet survey (Santos, Israelian, & Mayor 2001). The targets were chosen following two basic criteria: they make part

We present a photometric survey of bright southern stars carried out using the DENIS instrument equipped with attenuating filters. The observations were carried out not using the survey mode of DENIS, but with individual target pointings. This project was stimulated by the need to obtain near-infrared photometry of stars to be used in early

We present a detailed spectroscopic investigation, spanning four winters, of the asymptotic giant branch (AGB) star IRAS 02091+6333. Zijlstra & Weinberger (cite{ZW}) found a giant wall of dust around this star and modelled this unique phenomenon. However their work suffered from the quality of the optical investigations of the central object. Our

Very valuable information can be obtained by studying surface chemical abundances in stars with orbiting planets. Possible interactions between extrasolar planets and their parent stars can be studied using light elements as lithium and beryllium, which are excellent tracers of mixing mechanisms operating in the stellar interior. A wide sample of

Clusters of galaxies produce negative features at wavelengths λ > 1.25 mm in cosmic microwave background (CMB) maps by means of the thermal Sunyaev-Zel'dovich (SZ) effect, while point radio sources produce positive peaks. This fact implies that a distribution of unresolved SZ clusters could be detected using the negative asymmetry introduced in the