Related papers: CS22964-161: A Double-Lined Carbon- and s-Process-…
Hot subdwarf B stars (sdBs) are evolved core helium-burning stars with very thin hydrogen envelopes. In order to form an sdB, the progenitor has to lose almost all of its hydrogen envelope right at the tip of the red giant branch. In binary…
We report on the elemental abundances of the carbon-enhanced metal-poor (CEMP) star J2217+2104 discovered by our metal-poor star survey with LAMOST and Subaru. This object is a red giant having extremely low Fe abundance ([Fe/H]=-4.0) and…
We present a detailed chemical abundance analysis of HE 1300+0157, a subgiant with [Fe/H]=-3.9. From a high-resolution, high-S/N Subaru/HDS spectrum we find the star to be enriched in C ([C/Fe]_1D ~ +1.4) and O ([O/Fe]_1D ~ +1.8). With the…
We report the results of a comprehensive study of the spectroscopic binary (SB2) system HD 34736 hosting two chemically peculiar (CP) late B-type stars. Using new and archival observational data, we characterise the system and its…
The atmosphere of the extremely high-velocity (530-920 km/s) early B-type star HD271791 is enriched in $\alpha$-process elements, which suggests that this star is a former secondary component of a massive tight binary system and that its…
From high resolution (R = 45,000), high signal-to-noise (S/N > 400) spectra gathered with the Immersion Grating Infrared Spectrograph (IGRINS) in the H and K photometric bands, we have derived elemental abundances of two bright, well-known…
Context: Few exoplanets around hot stars with radiative envelopes have been discovered, although new observations from the TESS mission are improving this. Stars with radiative envelopes have little mixing at their surface, and thus their…
High resolution CASPEC and EMMI spectra (R$\approx$10$^4$) of the faint metal- deficient candidates CS 22891--209, CS 22897--8, CS 22948--66 and CS 22968--14 taken from the survey of Beers, Preston and Shectman (1985, BPS) are analyzed for…
We present high-resolution spectroscopic observations of the \ion{Li}{1} resonance line in a sample of 62 stars that belong to 31 common-proper motion pairs with twin F or G-type components. Photospheric abundances of lithium were derived…
Lithium rich stars in globular clusters are rare. In fact, only 14 have been found so far, in different evolutionary phases from dwarfs to giants. Different mechanisms have been proposed to explain this enhancement, but it is still an open…
Certain carbon-enhanced metal-poor stars likely obtained their composition via pollution from some of the earliest generations of asymptotic giant branch stars and as such provide important clues to early Universe nucleosynthesis. Recently,…
We have obtained high-resolution (R $\simeq$ 50,000 or 90,000), high-quality (S/N $\ga$ 100) spectra of 22 very metal-poor stars ([Fe/H] $\la$ -2.5) with the High Dispersion Spectrograph fabricated for the 8.2m Subaru Telescope. The spectra…
Context: This paper is part of a larger project in which we study the chemical abundances of extra-galactic post-AGB stars with the ultimate goal of improving our knowledge of the poorly understood AGB third dredge-up mixing processes and…
We report on a programme to monitor the radial velocities of a sample of candidate and confirmed carbon-enhanced, metal-poor (CEMP) stars. We observed 45 targets using the Echelle Spectrographs of three 4m class telescopes. Radial…
A substantial fraction of the lowest metallicity stars show very high enhancements in carbon. It is debated whether these enhancements reflect the stars' birth composition, or if their atmospheres were subsequently polluted, most likely by…
This study presents a detailed chemical, kinematic, and orbital dynamic analysis of five metal poor stars in the solar neighborhood: HD 2665, HD 5916, HD 122956, HD 189349, and HD 218857. Using high-resolution spectroscopic data from the…
The mechanisms responsible for chemical depletion across diverse astrophysical environments are not yet fully understood. In this paper, we investigate chemical depletion in post-AGB/post-RGB binary stars hosting second-generation…
Detached eclipsing binaries are remarkable systems to provide accurate fundamental stellar parameters. The fundamental stellar parameters and the metallicity values of stellar systems are needed to deeply understand the stellar evolution…
We obtained high resolution, high S/N spectroscopy for the very metal-poor star HD122563 with the Subaru Telescope High Dispersion Spectrograph. Previous studies have shown that this object has excesses of light neutron-capture elements,…
High resolution spectra of 5 candidate metal-weak thick-disc stars suggested by Beers & Sommer-Larsen (1995) are analyzed to determine their chemical abundances. The low abundance of all the objects has been confirmed with metallicity…