Related papers: TOPoS: III. An ultra iron-poor multiple CEMP syste…
Observations suggest that the interstellar medium (ISM) might have been highly enriched in carbon at very early times. We explore nucleosynthesis in massive carbon-enhanced metal-poor (CEMP) stars of $12$--$40\,\mathrm{M}_\odot$ formed from…
Abundances of five elements, Na, Mg, Al, Si, and Sr, are investigated for 44 very metal-poor stars (-4.0 < [Fe/H] < -1.5) in the Galactic halo system based on an Local Thermodinamic Equilibrium (LTE) analysis of high-resolution…
We present the results of analysis of ``snapshot'' spectra of 253 metal-poor halo stars -3.8 < [Fe/H] < -1.5 obtained in the HERES survey. The spectra are analysed using an automated line profile analysis method based on the Spectroscopy…
We report on the first high-resolution spectroscopic analysis of HE0020-1741, a bright (V=12.9), ultra metal-poor ([Fe/H] = -4.1), carbon-enhanced ([C/Fe] = +1.7) star selected from the Hamburg/ESO Survey. This star exhibits low abundances…
The metal content of a galaxy's interstellar medium reflects the interplay between different evolutionary processes such as feedback from massive stars and the accretion of gas from the intergalactic medium. Despite the expected abundance…
We investigate the origin of carbon-enhanced metal-poor (CEMP) stars starting from the recently discovered $\rm [Fe/H]<-7.1$ star SMSS J031300 (Keller et al. 2014). We show that the elemental abundances observed on the surface of SMSS…
The chemical abundances for five metal-poor stars in and towards the Galactic bulge have been determined from H-band infrared spectroscopy taken with the RAVEN multi-object adaptive optics science demonstrator and the IRCS spectrograph at…
We present stellar parameters and abundances of 13 elements for 18 very metal-poor (VMP; [Fe/H] $<$ -2.0) stars, selected as extremely metal-poor (EMP; [Fe/H] $<$ -3.0) candidates from SDSS and LAMOST survey. High-resolution spectroscopic…
We present a comprehensive abundance analysis of 20 elements for 16 new low-metallicity stars from the Chemical Abundances of Stars in the Halo (CASH) project. The abundances have been derived from both Hobby-Eberly Telescope High…
We present a double-blind analysis of high-dispersion spectra of seven red giant members of the Bo\"{o}tes I ultra-faint dwarf spheroidal galaxy, complemented with re-analysis of a similar spectrum of an eighth member star. The stars cover…
We present elemental abundance results for HE 2148-2039 and HE 2155-2043 based on a detailed high-resolution spectroscopic analysis. The high-resolution SUBARU/HDS spectra used for our analysis have a resolution of R~60 000. Although…
We present detailed chemical element abundance ratios of 17 elements in three metal poor stars in the Ursa Minor dwarf spheroidal galaxy, which we combine with extant data from the literature to assess the predictions of a novel suite of…
Stellar metallicity strongly correlates with the presence of planets and their properties. To check for new correlations between stars and the existence of an orbiting planet, we determine precise stellar parameters for a sample of…
In an effort to extend the still limited sample of s-process enriched post-AGB stars, high-resolution, high signal-to-noise VLT+UVES spectra of the optical counterparts of the infrared sources IRAS06530-0213 and IRAS08143-4406 were…
We present an analysis of the UVES high-resolution spectroscopic observations at the 8.2m VLT of J0023+0307, a main-sequence extremely iron-poor dwarf star. We are unable to detect iron lines in the spectrum but derive [Fe/H]<-6.1 from the…
Silicon and Strontium are key elements to explore the nucleosynthesis and chemical evolution of the Galaxy by measurements of very metal-poor stars. There are, however, only a few useful spectral lines of these elements in the optical range…
Large surveys of very metal-poor stars have revealed in recent years that a large fraction of these objects were carbon-rich, analogous to the more metal-rich CH-stars. The abundance peculiarities of CH-stars are commonly explained by…
We have obtained high-resolution high signal-to-noise spectra of the SI near-infrared doublet at 8694 A in eight metal-poor stars with metallicities in the range -0.6 <[Fe/H]< -3.0. Elemental sulphur abundances were derived for six targets…
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 present a detailed abundance analysis based on high resolution and high signal-to-noise spectra of eight extremely metal poor (EMP) stars with [Fe/H] < -3.5$ dex, four of which are new. Only stars with 4900 < Teff< 5650 K are included.…