相关论文: Hyperfine Structure and Abundances of Heavy Elemen…

We have derived the ionization ratios of twelve elements in the atmosphere of the star 68 Tauri (HD 27962) using an ATLAS9 model atmosphere with 72 layers computed for the effective temperature and surface gravity of the star. We then…

We derive the mixture of odd to even barium isotopes in the atmosphere of the metal-poor subgiant HD140283 from the analysis of the Ba II transition at 455.4 nm in a high-resolution high signal-to-noise spectrum of the star. The detailed…

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…

A classical Local Thermodynamic Equilibrium analysis, based on high-resolution spectroscopic data, is performed for a sample of three potential barium dwarf candidates and one star already recognized as such. We derived their atmospheric…

Aims. The metal-poor star BPM 3066 belongs to the retrograde halo and presents unexpectedly strong spectral features of lithium. To gain insight into the origin of this peculiar abundance, we investigate the chemistry and kinematic…

We observed high-resolution optical spectra of 11 RV Tauri stars without IR excess, with the primary goal of searching for chemical depletion patterns. Using equivalent widths of absorption lines, we calculated photospheric parameters and…

We present elemental abundance results from high resolution spectral analysis of three nitrogen-enhanced barium stars. The analysis is based on spectra obtained with the FEROS attached to 1.52m telescope at ESO, Chile. The spectral…

We present a chemical abundance study of giant stars in the Galactic open cluster NGC 5822, which hosts two barium stars (#002 and #201) and three lithium-enriched giants (#006, #102, and #240). Using high-resolution optical and…

Recent photospheric abundance studies of galactic field RV Tauri stars show that depletion of refractory elements is rather common in these evolved objects. The process that creates this chemical anomaly is not understood well, but it…

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)…

[Abridged] Barium stars are moderately rare, chemically peculiar objects, which are believed to be the result of the pollution of an otherwise normal star by material from an evolved companion on the asymptotic giant branch (AGB). We aim to…

Based on the high resolution and high signal-to-noise spectra, we derived the chemical abundances of 20 elements for 20 barium (Ba-) stars. For the first time, the detailed abundances of four sample stars, namely HD 92482, HD 150430, HD…

The origin and evolution of neutron-capture elements in our Galaxy is poorly understood. In this work, we have attempted to understand the Galactic s-process nucleosynthesis using barium stars as probes. We have performed high resolution…

We test the capabilities of 0.4 m telescopes equipped with an \'{e}chelle spectrograph to derive fundamental parameters and elemental abundances of four late-B type stars: HR 342, HR 769, HR 1284, and HR 8705. The medium resolution…

Context. Theoretical results showed the possibility that neutron capture elements were produced in the early Universe by two different sources: a frequent s-process source hosted by rotating massive stars, and a rare r-process source hosted…

Chemical compositions of four barium stars HD 26886, HD 27271, HD 50082 and HD 98839 are studied based on high resolution, high signal-to-noise Echelle spectra. Results show that all of them are disk stars. Their \alpha and iron peak…

As part of a large survey of halo and thick disc stars, we found one halo star, HD 106038, exceptionally overabundant in beryllium. In spite of its low metallicity, [Fe/H] = -1.26, the star has log(Be/H) = -10.60, which is similar to the…

Detailed chemical composition studies of stars with enhanced abundances of neutron-capture elements can provide observational constraints for neutron-capture nucleosynthesis studies and clues for understanding their contribution to the…

We present a detailed analysis of 26 barium stars, including dwarf barium stars, providing their atmospheric parameters (Teff, log g, [Fe/H], vt) and elemental abundances. We aim at deriving gravities and luminosity classes of the sample…

Lithium rich giant stars are rare objects. For some of them, Li enrichment exceeds abundance of this element found in solar system meteorites, suggesting that these stars have gone through a Li enhancement process. We identified a Li rich…