Related papers: An ancient system hidden in the Galactic plane?
As a galaxy evolves, its chemical composition changes and the abundance ratios of different elements are powerful probes of the underlying evolutionary processes. Phosphorous is an element whose evolution has remained quite elusive until…
We present a homogeneous set of accurate atmospheric parameters for a sample of eleven very metal-poor (-3.32 <= [Fe/H] <= -2.61) stars in the Sextans dwarf spheroidal galaxy (dSph) and the non-local thermodynamic equilibrium (NLTE)…
An early history of metal enrichment in the Galactic halo is studied. We investigate chemical inhomogeneity by using a stochastic chemical evolution model. The model confronts with metallicity distribution function of long-lived halo stars…
Chemical abundances for 23 candidate subgiant stars have been derived with the aim at exploring their usefulness for studies of galactic chemical evolution. High-resolution spectra from ESO CAT-CES and NOT-SOFIN covered 16 different…
New space missions, such as NASA TESS or ESA PLATO, will focus on bright stars, which have been largely ignored by modern large surveys, especially in the northern sky. Spectroscopic information is of paramount importance in characterising…
We present an analysis of very metal-poor (VMP) and metal-poor stars ($-3.0 < \mathrm{Fe/H]} < -1.5$) in the Gaia BP/RP or XP catalog, which reveals two distinct metallicity distribution functions (MDFs) in regions of the Galactic disk…
We report the spectroscopic analysis of 20 halo ab-type RR Lyrae stars with heliocentric distances between 15 and 165 kpc, conducted using medium-resolution spectra from the Magellan Inamori Kyocera Echelle (MIKE) spectrograph. We obtain…
Context. The study of old, metal-poor stars deepens our knowledge on the early stages of the universe. In particular, the study of these stars gives us a valuable insight into the masses of the first massive stars and their emission of…
We present a statistical analysis of the properties of a large sample of dynamically hot old stellar systems, from globular clusters to giant ellipticals, which was performed in order to investigate the origin of ultra-compact dwarf…
Context. Elemental abundances are of prime importance to help us reconstruct the origin and evolution of stars and galaxies in our Universe. Sulfur abundances have not been as heavily studied as other elements, so some details regarding its…
The metallicity distribution function (MDF) of the Galactic bulge features a multi-peak shape, with a metal-poor peak at [Fe/H]=-0.3 dex and a metal-rich peak at [Fe/H]=+0.3 dex. This bimodality is also seen in [alpha/Fe] versus [Fe/H]…
We study the chemical abundances of a wide sample of 142 Galactic planetary nebulae (PNe) with good quality observations, for which the abundances have been derived more or less homogeneously, thus allowing a reasonable comparison with…
We report a detailed abundance analysis for HE0107-5240, a halo giant with [Fe/H]_NLTE=-5.3. This star was discovered in the course of follow-up medium-resolution spectroscopy of extremely metal-poor candidates selected from the digitized…
We measure oxygen and nitrogen abundances for 14 star-forming emission line galaxies (ELGs) at 0.11<z<0.5 using Keck/LRIS optical spectroscopy. The targets exhibit a range of metallicities from slightly metal-poor like the LMC to…
ABRIDGED: To compare the chemistries of stars in the Milky Way dSph galaxies with stars in the Galaxy, we have compiled a large sample of Galactic stellar abundances from the literature. As found in previous studies, the [alpha/Fe] ratios…
[Abridged] We present a medium-resolution spectroscopic survey of late-type giant stars at mid-Galactic latitudes of (30$^{\circ}<|b|<60^{\circ}$), designed to probe the properties of this population to distances of $\sim$9 kpc. Because M…
We present radial velocities and [Fe/H] abundances for 340 stars in the Fornax dwarf spheroidal from R~16,000 spectra. The targets have been obtained in the outer parts of the galaxy, a region which has been poorly studied before. Our…
During its evolution, the Milky Way (MW) incorporated numerous dwarf galaxies, particularly low-mass systems. The surviving dwarf galaxies orbiting the MW serve as exceptional laboratories for studying the unique properties of these…
The oldest stars in the Milky Way are metal-poor with [Fe/H] < -- 1.0, displaying peculiar elemental abundances compared to solar values. The relative variations in the chemical compositions among stars is also increasing with decreasing…
The most metal-poor stars (e.g. [Fe/H] $\leq-2.5$) are the ancient fossils from the early assembly epoch of our Galaxy, very likely before the formation of the thick disc. Recent studies have shown that a non-negligible fraction of them…