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...

SDSS J082625.70+612515.10 (V = 11.4 [Fe/H] = ‑3.1) and SDSS J134144.60+474128.90 (V = 12.4 [Fe/H] = ‑3.2) were observed with the SDSS 2.5m telescope as part of...

We present a detailed spectroscopic analysis of horizontal branch stars in the globular cluster NGC 3201. We collected optical (4580–5330 Å), high-resolution (...

We present a detailed spectroscopic analysis of RR Lyrae (RRL) variables in the globular cluster NGC 5139 (ω Cen). We collected optical (4580–5330 Å), high...

Context. The study of the radial variations of metallicity across the Galactic disc is a powerful method for understanding the history of star formation and...