相关论文: Solar twins and the Barium puzzle

We present a study of the abundance of Be stars in open clusters as a function of the cluster age, using whenever possible ages determined through Stromgren uvby photometry. For the first time in studies of this kind we have considered…

We use our new, flux-calibrated stellar population model of absorption-line indices to derive ages, metallicities, and various element abundance ratios from integrated light spectroscopy of galactic globular clusters. The ages agree well…

Estimates of the bulk metal abundance of the Sun derived from the latest generation of model atmospheres are significantly lower than the earlier standard values. In Paper I we demonstrated that a low solar metallicity is inconsistent with…

We explore the possible connection between the open cluster IC 2391 and the unbound Argus association identified by the SACY survey. In addition to common kinematics and ages between these two systems, here we explore their chemical…

Abundances of Mg, Ca, Sc, Cr, Fe, and Ni are derived for A stars of five nearby open clusters of various ages using high resolution spectroscopy. We point out a correlation between the abundance of Ca and that of Sc, suggesting that the…

Context. The pursuit of more realistic spectroscopic modelling and consistent abundances has led us to begin a new series of papers designed to improve current solar and stellar abundances of various atomic species. To achieve this, we have…

We report detailed chemical abundance analysis of 27 RGB stars towards the Galactic bulge in Baade's Window for elements produced by massive stars: O, Na, Mg, Al, Si, Ca and Ti. All of these elements are overabundant in the bulge relative…

We have performed a detailed abundance analysis of the content of s-process elements of two dwarf stars with suspected overabundace of those elements. Such stars belong to a special kinematic sample of the solar neighborhood, with peculiar…

HARPS spectra with signal-to-noise ratios S/N > 600 at 6000 A were analysed with MARCS model atmospheres to obtain 1D LTE abundances of C, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Sr, and Y for 72 nearby solar-type stars with metallicities in…

Abundances of beryllium in metal-poor stars scale linearly with metallicity down to [Fe/H] ~ -3.0. In the stars where Be has been detected at this extremely metal-poor regime, an increased abundance scatter has been previously reported.…

With an aim of clarifying the extent and parameter-dependence of compositional anomaly of barium in A-type stars, Ba abundances were spectroscopically determined based on BaII 6141/6496 lines for 89 (23 A-type and 66 F--G-type)…

To investigate the Ba and Eu abundances for a sample of 63 giant stars in the globular cluster M15. This is the largest sample of M15 giants stars for which Ba abundances have been determined and, due to the target selection of the original…

We derive the abundance of 19 elements in a sample of 64 stars with fundamental parameters very similar to solar, which minimizes the impact of systematic errors in our spectroscopic 1D-LTE differential analysis, using high-resolution…

We apply probabilistic generative modelling of colour-magnitude diagrams to six young Galactic open star clusters and determine their mass functions, binary mass-ratio distributions, and the frequencies of binary stars. We find that younger…

The chemical abundances of elements such as barium and the lanthanides are essential to understand the nucleosynthesis of heavy elements in the early Universe as well as the contribution of different neutron capture processes (for example…

The detailed abundance patterns of the stars within galaxies provide a unique window into the history of star formation (SF) at early times. Two widely used `chronometers' include the alpha and iron-peak elements, which are created on short…

The compositions of stars are a critical diagnostic tool for many topics in astronomy such as the evolution of our Galaxy, the formation of planets, and the uniqueness of the Sun. Previous spectroscopic measurements indicate a large…

The abundance of beryllium in the oldest, most metal-poor stars acts as a probe of early star formation and Galactic chemical evolution. We have analyzed high-resolution, high signal-to-noise Keck/HIRES spectra of 24 stars with [Fe/H] from…

We present the results of determination of the barium abundance considering the non-LTE (NLTE) effects in 172 dwarf stars in the metallicity range of -1< [Fe/H] <+0.3, assigned to different Galactic substructures by kinematic criteria. We…

We present B, V, R, and H alpha photometry of 8 clusters in the Small Magellanic Cloud, 5 in the Large Magellanic Cloud, and 3 Galactic clusters, and use 2 color diagrams (2-CDs) to identify candidate Be star populations in these clusters.…