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...

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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...

ζ Oph, HD 149757, is an O9.5 Vnn star with a very high projected rotational velocity (v sin i ≥ 340 km s-1). It is also a classical runaway star due to its high...

We present echelle spectroscopy in the 3500- to 7060-Å range for two positions of the Orion nebula. The data were obtained using the 2.1-m telescope at...

The Sun provides a standard reference against which we compare the chemical abundances found anywhere else in the Universe. Nevertheless, there is not a unique...

Context. The chemical composition of young massive clusters (YMCs) provides stellar population information on their host galaxy. As potential precursors of...