Related papers: Probing M subdwarf metallicity with an esdK5+esdM5…

Spectra of unevolved metal-poor halo stars uniquely reflect the elemental abundances incorporated during the earliest Galactic epoch. Their heavy-element content is well understood as the products of neutron capture on iron-peak elements.…

Detailed chemical composition of stars is of prime interest for a range of topics in modern stellar astrophysics, such as the chemical evolution of the Galaxy or the formation, composition, and structure of exoplanets. In this work, we…

We present a model-fit pipeline to determine the stellar parameters of M-type dwarfs, which is an improvement upon our previous work described in Hejazi et al. 2020. We apply this pipeline to analyze the low-resolution (R~2000) spectra of…

We present the first release of a large-scale study of relatively bright (V < 13.5) metal-poor stars observed with the Southern African Large Telescope (SALT), based on high-resolution spectra of 50 stars with a resolving power of R ~…

We present a method for the determination of [alpha/Fe] ratios from low-resolution (R = 2000) SDSS/SEGUE stellar spectra. By means of a star-by-star comparison with degraded spectra from the ELODIE spectral library and with a set of…

We have used high-resolution, high-S/N ratio spectra from the UVES spectrograph at the ESO VLT telescope. Long-term radial-velocity measurements and broad-band photometry allow us to determine improved orbital elements and stellar…

AR Aur A+B is a close binary of astrophysical interest, because dissimilar surface compositions are reported between similar late B-type dwarfs. A new spectroscopic study on this system was carried out based on the disentangled spectra, in…

We present interferometric diameter measurements of 21 K- and M- dwarfs made with the CHARA Array. This sample is enhanced by literature radii measurements to form a data set of 33 K-M dwarfs with diameters measured to better than 5%. For…

[ABRIDGED] Metal-rich globular clusters provide important tracers of the formation of our Galaxy. Moreover, and not less important, they are very important calibrators for the derivation of properties of extra-galactic metal-rich stellar…

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…

Elemental abundance measurements have been obtained for a sample of 18 very metal-poor stars using spectra obtained with the Subaru Telescope High Dispersion Spectrograph. Seventeen stars, among which 16 are newly analyzed in the present…

We have performed a differential, line-by-line, chemical abundance analysis, ultimately relative to the Sun, of nine very metal-poor main sequence halo stars, near [Fe/H]=$-$2 dex. Our abundances range from…

We give an update on our 0Z Survey to find more extremely metal poor (EMP) stars with [Fe/H] < -3 dex through mining the database of the Hamburg/ESO Survey. We present the most extreme such stars we have found from ~1550 moderate resolution…

Abundances for Fe, O, and the alpha-elements (Mg, Si, Ca, and Ti) have been derived from high resolution spectra of a sample of about one hundred dwarfs with high precision parallaxes measured by HIPPARCOS. The stars have metal abundances…

Edelmann (2003) identified two chemically peculiar hot subdwarfs, PG 0909+276 and UVO 0512-08, as having very high overabundances of iron-group elements. We obtained high-resolution ultraviolet spectroscopy in order to measure abundances of…

The formation of sdBs is still puzzling, as is the chemical composition of their atmospheres. While helium and other light elements are depleted relative to solar values, heavy elements are highly enriched. Diffusion processes in the hot,…

Knowledge of the metallicities of M dwarfs rests predominantly on the photometric calibration of Bonfils and collaborators, which predicts that M dwarfs in the solar neighborhood, including those with known planets, are systematically…

We present K band spectra for 133 nearby (d < 33 parsecs) M dwarfs, including 18 M dwarfs with reliable metallicity estimates (as inferred from an FGK type companion), 11 M dwarf planet hosts, more than 2/3 of the M dwarfs in the Northern 8…

We present Iron, Magnesium, Calcium, and Titanium abundances for 235 stars in the central region of the Sagittarius dwarf spheroidal galaxy (within 9.0 arcmin ~70 pc from the center) from medium-resolution Keck/DEIMOS spectra. All the…

The most metal-poor stars are the relics of the early chemical evolution of the Galaxy. Their chemical composition is an important tool to constrain the nucleosynthesis in the first generation of stars. The aim is to observe a sample of…