Related papers: Chemical Composition of the RS CVn-TYPE Star Lambd…
As a well-established procedure for the vast majority of normal main-sequence stars, determination of atmospheric and stellar parameters turns to be a challenging process in case of magnetic chemically peculiar stars. Inhomogeneous…
We performed a uniform and detailed abundance analysis of 12 refractory elements (Na, Mg, Al, Si, Ca, Ti, Cr, Ni, Co, Sc, Mn, and V) for a sample of 257 G- and K-type evolved stars from the CORALIE planet search program. To date, only one…
We present a comprehensive analysis of the detailed chemical abundances for a sample of 11 metal-poor, very metal-poor and extremely metal-poor stars ([Fe/H] = -1.65 to [Fe/H] = -3.0) as part of the HESP-GOMPA (Galactic survey Of Metal Poor…
Stellar kinematic groups are kinematical coherent groups of stars that might have a common origin. These groups are dispersed throughout the Galaxy over time by the tidal effects of both Galactic rotation and disc heating, although their…
We report on the discovery of five carbon-enhanced metal-poor (CEMP) stars in the metallicity range of $-3.3<$ [Fe/H] $<-2.4$. These stars were selected from the LAMOST DR3 low-resolution (R$ \sim$ 2,000) spectroscopic database as…
Context: The study of chemical abundance patterns in globular clusters is of key importance to constrain the different candidates for intra-cluster pollution of light elements. Aims: We aim at deriving accurate abundances for a large range…
The atmospheric structure of chemically peculiar stars deviates from that of normal stars with similar fundamental parameters due to unusual chemistry, abundance inhomogeneities and the presence of strong magnetic field. These effects are…
The eclipsing and double-lined spectroscopic binary system V453 Cygni consists of two early B-type stars, one of which is nearing the terminal age main sequence and one which is roughly halfway through its main sequence lifetime. Accurate…
High-resolution, high-signal-to-noise (<S/N> = 85) spectra have been obtained for five stars -- CD-24:17504, CD-38:245, CS 22172-002, CS 22885-096, and CS 22949-037 -- having [Fe/H] < -3.5 according to previous lower S/N material. LTE…
Massive stars play an important role in the Universe. Unlike low-mass stars, the formation of these objects located at great distances is still unclear. It is expected to be governed by some combination of self-gravity, turbulence, and…
Massive star-forming regions exhibit an extremely rich and diverse chemistry, which in principle provides a wealth of molecular probes, as well as laboratories for interstellar prebiotic chemistry. Since the chemical structure of these…
The accuracy of measuring the basic parameters of neutron stars is limited in particular by uncertainties in chemical composition of their atmospheres. For example, atmospheres of thermally - emitting neutron stars in supernova remnants…
The circumstellar envelopes (CSEs) of asymptotic giant branch (AGB) stars harbour a rich variety of molecules and are sites of complex chemistry. Our current understanding of the circumstellar chemical processes of carbon-rich AGB stars is…
Deriving stellar atmospheric parameters and chemical abundances from stellar spectra is crucial for understanding the evolution of the Milky Way. By performing a fitting with MARCS model atmospheric theoretical synthetic spectra combined…
With a luminosity > 10^5 Lsun and a mass-loss rate of about 2.10-4 Msun/yr, the red supergiant VY CMa truly is a spectacular object. Because of its extreme evolutionary state, it could explode as supernova any time. Studying its…
CONTEXT:The detailed chemical abundances of extremely metal-poor (EMP) stars are key guides to understanding the early chemical evolution of the Galaxy. Most existing data are, however, for giant stars which may have experienced internal…
Slow rotation and absence of strong mixing processes in atmospheres of chemically peculiar stars develop ideal conditions for the appearance of abundance anomalies through the mechanism of microscopic particle diffusion. This makes these…
We investigate the stellar atmospheres of the two components of the Herbig Ae SB2 system AK Sco to determine the elements present in the stars and their abundance. Equal stellar parameters T_eff = 6500K and log g = 4.5 were used for both…
Photospheric abundances are presented for 27 elements from carbon to europium in 181 F-G dwarfs from a differential LTE analysis of high-resolution and high signal-to-noise spectra. Stellar $T_{\rm eff}$ were adopted from an infrared flux…
Context: The small- to intermediate-mass ($M <0.8 M_\odot$), most metal-poor stars that formed in the infancy of the Universe are still shining today in the sky. They are very rare, but their discovery and investigation brings new knowledge…