相关论文: The evolved pulsating CEMP star HD112869

A significant fraction of all metal-poor stars are carbon-rich. Most of these carbon-enhanced metal-poor (CEMP) stars also show enhancement in elements produced mainly by the s-process (CEMP-s stars) and evidence suggests that the origin of…

Four members of the new class of pulsating sdB stars are analysed from Keck HIRES spectra using NLTE and LTE model atmospheres. Atmospheric parameters (Teff, log g, log(He/H)), metal abundances and rotational velocities are determined.…

We report the discovery of a new subclass of carbon-enhanced metal-poor (CEMP) stars, characterized by high absolute carbon abundances (A(C) > 7.39) and extremely low metallicity ([Fe/H] $<=$ -3.1) but notably lacking enhancements in…

We present analysis of a new pulsating helium-atmosphere (DB) white dwarf, EPIC~228782059, discovered from 55.1~days of {\em K2} photometry. The long duration, high quality light curves reveal 11 independent dipole and quadruple modes, from…

The detailed composition of most metal-poor halo stars has been found to be very uniform. However, a fraction of 20-70% (increasing with decreasing metallicity) exhibit dramatic enhancements in their abundances of carbon - the so-called…

We present the first time abundance analysis of a very metal-poor carbon-enhanced star CD-27 14351 based on a high resolution (R ~ 48000) FEROS spectrum. Our abundance analysis performed using Local Thermodynamic Equilibrium (LTE) model…

We present, for the first time, a detailed abundance analysis of the carbon star HE 1104$-$0957 based on high resolution (R${\sim}$ 50\,000) spectra. Our analysis shows that the object is an extremely metal-poor star with [Fe/H] $\sim$…

We present a 1D LTE chemical abundance analysis of the very bright (V=9.1) Carbon-Enhanced Metal-Poor (CEMP) star BD +44 493, based on high-resolution, high signal-to-noise spectra obtained with Subaru/HDS. The star is shown to be a…

The known Mega and Hyper Metal-Poor (MMP-HMP) stars with [Fe/H]<-6.0 and <-5.0, respectively, likely belong to the CEMP-no class, i.e. carbon-enhanced stars with low or absent second peak neutron capture elements. They are likely second…

Carbon-enhanced metal poor stars (CEMP) form a significant proportion of the metal-poor stars, their origin is not well understood. Three very metal-poor C-rich turnoff stars were selected from the SDSS survey, observed with the ESO VLT…

Dwarf carbon stars are dominated by members of the Galactic halo and are thus likely carbon-enhanced metal-poor stars. In this work, a sample of 879 bona fide dwarf carbon stars are characterized by their ground-based light curves, and p<15…

PG1159 stars are hot, hydrogen-deficient (pre-) white dwarfs with atmospheres mainly composed of helium, carbon, and oxygen. The unusual surface chemistry is the result of a late helium-shell flash. Observed element abundances enable us to…

We present a detailed abundance analysis of 23 elements for a newly discovered carbon-enhanced metal-poor (CEMP) star, HE 0414-0343, from the Chemical Abundances of Stars in the Halo (CASH) Project. Its spectroscopic stellar parameters are…

We present an analysis of the heavy-element abundances of HD 196944, a carbon-enhanced metal-poor (CEMP) star enriched with elements produced by the slow neutron-capture process (s-process). We obtained a new high-resolution ultraviolet…

We describe a method for the determination of stellar [C/Fe] abundance ratios using low-resolution (R = 2000) stellar spectra from the SDSS and SEGUE. By means of a star-by-star comparison with a set of SDSS/SEGUE spectra with available…

We have carried out a detailed abundance analysis for a sample of 16 carbon stars found among candidate extremely metal-poor (EMP) stars from the Hamburg/ESO Survey. We find that the Fe-metallicities for the cooler C-stars (Teff ~ 5100K)…

The observed abundance diversities among the CEMP stars can shed light on the formation and evolution of elements in the early Galaxy. In this work, we present results obtained from a detailed abundance analysis of a sample of seven…

Recent BRITE-Constellation space photometry of the slowly rotating, magnetic $\beta$ Cep pulsator $\xi^1$ CMa permits a new analysis of its pulsation properties. Analysis of the two-colour BRITE data reveals the well-known single pulsation…

The origin of carbon-enhanced metal-poor stars enriched with both s and r elements is highly debated. Detailed abundances of these types of stars are crucial to understand the nature of their progenitors. The aim of this investigation is to…

From high-resolution VLT/UVES spectra (R~43,000), we determine abundances or upper limits for Li, C, N, O, and other important elements, as well as 12C/13C isotopic ratio for three Carbon enhanced metal poor stars. All three stars have…