相关论文: Spectroscopic Analysis of Two Carbon Rich Post-AGB…

We present a high resolution detailed abundance analysis for a sample of six post-AGB candidate stars, five of them had not been studied spectroscopically in the optical region. All the analyzed objects are IRAS sources identified as…

One of the puzzling findings in the study of the chemical evolution of (post-)AGB stars is why very similar stars (in terms of metallicity, spectral type, infrared properties, etc...) show a very different photospheric composition. We aim…

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 a detailed chemical analysis on the basis of high-resolution, high signal-to-noise optical spectra of two post-AGB objects IRAS 22223+4327 and IRAS 04296+3429. Both display the unidentified $21 \mu m$ feature in their IR-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 have derived elemental abundances for a sample of nine IRAS sources with colours similar to those of post-AGB stars. For IRAS 01259+6823, IRAS 05208-2035, IRAS 04535+3747 and IRAS 08187-1905 this is the first detailed abundance analysis…

To search for and study the instabilities in the atmospheres of selected post-AGB stars, we have performed a long-term high-resolution spectroscopy (R=60000) with the spectrograph NES of the 6-meter BTA telescope. Low-amplitude pulsations,…

This paper is part of a larger project in which we systematically study the chemical abundances of Galactic and extragalactic post-asymptotic giant branch (post-AGB) stars. Lead (Pb) is the final product of the s-process nucleosynthesis and…

High dispersion near-infrared spectra have been taken of seven highly-evolved, variable, intermediate-mass (4-6 Msun) AGB stars in the LMC and SMC in order to look for C, N and O variations that are expected to arise from third dredge-up…

Detailed atmospheric abundances have been calculated for a sample of A-G supergiant stars with IR fluxes and/or high galactic latitudes. HD 172481 and HD 158616 show clear indications of being post-AGB stars that have experienced third…

Stellar photospheres of post-asymptotic giant branch stars bear witness to the internal chemical enrichment processes, integrated over their entire stellar evolution. Here we study post-AGB stars in the Large Magellanic Cloud (LMC). With…

The first high-resolution (R~50,000) optical spectrum of the B-type star, LS III +52 24, identified as the optical counterpart of the hot post-AGB candidate IRAS 22023+5249 (I22023) is presented. We report the detailed identifications of…

Aims: We investigate the change in the surface abundance of $^{12}$C during the evolution along the AGB, aiming to constrain third dredge-up models. Methods: High-resolution, near-infrared spectra of a sample of AGB stars in the LMC cluster…

Lithium and zirconium abundances (the latter taken as representative for s-process enrichment) are determined for a large sample of massive Galactic O-rich AGB stars, for which high resolution optical spectroscopy has been obtained…

We have done a detailed abundance analysis of four unexplored candidate post- Asymptotic Giant Branch(AGB) stars IRAS 13110 - 6629, IRAS 17579 - 3121, IRAS 18321 - 1401 and IRAS 18489 - 0629 using high resolution spectra. We have…

The observational data guiding the theoretical chemical evolutionary models of AGB stars come mainly from the analysis of intrinsic and extrinsic s-process enriched objects. The first are the stars of the M-MS-S-SC-C star sequence which is…

We present in this paper a homogeneous photospheric abundance study, on the basis of the analysis of high resolution optical spectra, of six post-AGB objects displaying a 21mic circumstellar dust feature in their IR spectrum. The F-G…

An abundance analysis has been conducted for a sample of nine post-AGB candidate stars; eight of them have not been explored before. We find four very promising objects like HD 105262, HD 53300 and CpD$-62^o5428$ among them. We find strong…

To better understand the mixing and mass loss experienced by low-mass stars as they ascend the asymptotic giant branch (AGB), I have gathered from the literature the abundances of CNO and s-process elements in post-AGB stars in Galactic…

By virtue of their spectral types, favourable bolometric corrections as well as their constrained distances, post-AGB stars in external galaxies offer unprecedented tests to AGB nucleosynthesis and dredge-up predictions. We focus here on…