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 Planetary Nebulae belonging to the spiral galaxy M 33. Central star temperatures and nebular parameters have been determined. In particular the chemical abundances of He/H, O/H, N/H, Ar/H

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 202206. In addition, we have also analyzed HD 13445 and HD 75289, already studied elsewhere. The abundances of C and alpha -elements O, S, Si, Ca and Ti are presented and discussed in the

Theoretical studies suggest that C/O and Mg/Si are the most important elemental ratios in determining the mineralogy of terrestrial planets. The C/O ratio controls the distribution of Si among carbide and oxide species, while Mg/Si gives information about the silicate mineralogy. We find mineralogical ratios quite different from those of the Sun

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 intermediate resolution spectra of seven B-type supergiants, lying within four OB associations covering a galactocentric distance of 5-12 kpc. The results are mainly based on an LTE analysis

Stellar kinematic groups are kinematically coherent groups of stars that may share a common origin. These groups spread through the Galaxy over time due to tidal effects caused by Galactic rotation and disk heating, however the chemical information survives. The aim of chemical tagging is to show that abundances of every element in the analysis

Stellar kinematic groups are kinematical coherent groups of stars that might have a common origin. These groups are dispersed throughout the Galaxy over time by the tidal effects of both Galactic rotation and disc heating, although their chemical content remains unchanged. The aim of chemical tagging is to establish that the abundances of every