Using spectroscopic data presented in Magrini et al. (cite{m03}), we have analyzed with the photoionization code CLOUDY 94.00 (Ferland et al. cite{ferland}) 11...

Context. It is well known that stars with giant planets are, on average, more metal-rich than stars without giant planets, whereas stars with detected low-mass...

We present the chemical analysis of a new set of stars known to harbor low mass companions, namely HD 1237, HD 52265, HD 82943, HD 83443, HD 169830, and HD...

Context. The most metal-poor stars are the relics of the early chemical evolution of the Galaxy. Their chemical composition is an important tool to constrain...

Aims: We aim to derive the chemical behavior of a significant sample of PNe and HII regions in the irregular galaxy NGC 6822. The selected objects are...

Context. The X-shooter Spectral Library (XSL) is a large empirical stellar library used as a benchmark for the development of stellar population models. The...

Absolute and differential chemical abundances are presented for the largest group of massive stars in M 31 studied to date. These results were derived from...

Context: Individual stars in dwarf spheroidal galaxies around the Milky Way Galaxy have been studied both photometrically and spectroscopically. Extremely metal...

We present NLTE abundances of CNO for a sample of four O9 stars in the Galaxy, together with new determinations of their stellar parameters, T_eff, log g...