相关论文: The Chemical Composition of Praesepe (M44)
We present the abundance measurements of several elements (Fe, Ca, Na, Ni, Ti, Al, Cr, Si) for 20 solar--type stars belonging to four Galactic open clusters: NGC 3680, IC 4651, Praesepe, and M 67. Oxygen abundances were in addition measured…
We present a detailed chemical analysis of 22 stars along the colour-magnitude sequence of the intermediate-age (1.7 Gyr) open cluster IC 4651. We find for the cluster a well-defined Fe abundance of [Fe/H]= 0.10 +/- 0.03 (internal errors),…
Context. Open clusters are ideal test particles to study the chemical evolution of the Galactic disc. However the existing high-resolution abundance determinations, not only of [Fe/H], but also of other key elements, is largely insufficient…
We study how chemical abundances of late B-, A- and early F-type stars evolve with time, and we search for correlations between the abundance of chemical elements and other stellar parameters, such as effective temperature and Vsini. We…
We present ages, [Fe/H] and abundances of the alpha elements Ca I, Si I, Ti I, Ti II, and light elements Mg I, Na I, and Al I for 31 globular clusters in M31, which were obtained from high resolution, high signal-to-noise ratio (SNR$>60$)…
The chemical composition of stars in open clusters provides the best information on the chemical evolution of stars via comparison of the main sequence stars with the evolved giants. This is a case study of the abundances in the dwarfs and…
Young open clusters (t<200 Myr) have been observed to exhibit several peculiarities in their chemical compositions, from a slightly sub-solar iron content, super-solar abundances of some atomic species (e.g. ionised chromium), and atypical…
Aims. The Chemical Evolution of R-process Elements in Stars (CERES) project aims to provide a homogeneous analysis of a sample of metal-poor stars ([Fe/H]<-1.5). We present the stellar parameters and the chemical abundances of elements up…
HARPS-N spectra with S/N > 250 and MARCS model atmospheres were used to derive abundances of C, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, and Y in ten stars from the Kepler LEGACY sample (including the binary pair 16 Cyg A and B) selected…
Recent work has shown that most globular clusters have at least two chemically distinct components, as well as cluster-to-cluster differences in the mean [O/Fe], [Mg/Fe], and [Si/Fe] ratios at similar [Fe/H] values. In order to investigate…
We present the results of determination of the age, helium mass fraction (Y) in terms of the used stellar evolutionary models, metallicity ([Fe/H]), and abundances of the elements C, O, Na, Mg, Ca, Ti, Cr and Mn for 26 globular clusters of…
Context: The chemical composition of stars is intimately linked to the Galaxy formation and evolution. Aims: We aim to trace the chemical evolution of the Galactic disk through the inspection of the [X/Fe]-age relations of 24 species from C…
We present a chemical composition analysis of 36 giant stars in mildly metal-poor globular cluster M5. In comparing the M5 results to those obtained in M4, a cluster previously considered to be a ``twin'' in age, metallicity and chemical…
Open clusters exquisitely track the Galactic disc chemical properties and its time evolution; a substantial number of studies and large spectroscopic surveys focus mostly on the chemical content of relatively old clusters (age $\gtrsim$ 1…
The physical processes driving chemical evolution in the Milky Way can be probed using the distribution of abundances in low-mass FGK type stars in space phase at different times. During their final stages of evolution stars experience…
HARPS spectra with S/N > 600 for 21 solar twin stars are used to determine very precise (sigma ~ 0.01 dex) differential abundances of C, O, Na, Mg, Al, Si, S, Ca, Ti, Cr, Fe, Ni, Zn, and Y in order to see how well [X/Fe] is correlated with…
High-resolution (R ~ 90,000) spectra of 34 nearby, young Sun-like stars were analyzed using stellar atmosphere models to estimate effective photosphere temperatures, surface gravities, and the abundance of certain heavy elements (C, Na, Mg,…
Detailed chemical abundance distributions for fourteen elements are derived for eight high-probability stellar members of the solar metallicity old open cluster M67 with an age of $\sim$4 Gyr. The eight stars consist of four pairs, with…
We present homogeneous abundances for Fe and some of the elements involved in the proton-capture reactions (O, Na, Mg, Al, and Si) for 202 red giants in 17 Galactic globular clusters (GCs) from the analysis of high resolution UVES spectra…
Abundances of 18 chemical elements have been derived for 16 A (normal and chemically peculiar CP) and 5 F dwarfs members of the Pleiades open cluster in order to set constraints on evolutionary models. The abundances, rotational velocities…