Detailed homogeneous abundance studies of 14 Galactic s-process enriched post-AGB stars: In search of lead (Pb)

Abstract

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 is predicted to have large overabundances with respect to other s-process elements in AGB stars of low metallicities. However, Pb abundance studies of enriched post-AGB stars in the Magellanic Clouds show the Pb overabundance is not observed. We used high-resolution UVES and HERMES spectra for detailed spectral abundance studies of our sample of 14 Galactic post-AGB stars. We do not find any clear evidence of Pb overabundances in our sample. Stars with T(eff) > 7500 K do not provide strong constraints on the Pb abundance. We conclude that the discrepancy between theory and observation increases towards lower metallicities. All objects, except IRAS 17279-1119, confirm the relation between neutron exposure [hs/ls] and third dredge-up efficiency [s/Fe], whereas no relation between metallicity and neutron exposure is detected within the metallicity range of our total sample (-1.4 < [Fe/H] < -0.2). The mild enrichment of IRAS 17279-1119 can probably be attributed to a cut-off of the AGB evolution due to binary interactions. To our knowledge, IRAS 17279-1119 is the first s-process enhanced Galactic post-AGB star known in a binary system and is a possible precursor of the extrinsic Ba dwarf stars. Lead-rich stars have yet to be found in post-AGB stars. extrinsic Ba dwarf stars. Lead-rich stars are yet to be found in post-AGB stars.

arXiv comment26 pages, 40 figures, Accepted for publication in Astronomy and Astrophysics, main journal

References in corpus (42)

• The chemical composition of the Sun
• Updated stellar yields from Asymptotic Giant Branch models
• The Dawes Review 2: Nucleosynthesis and stellar yields of low and intermediate-mass single stars
• The AKARI/IRC Mid-Infrared All-Sky Survey
• HERMES: a high-resolution fibre-fed spectrograph for the Mercator telescope
• New Grids of ATLAS9 Model Atmospheres
• Nucleosynthesis and mixing on the Asymptotic Giant Branch. III. Predicted and observed s-process abundances
• Evolution, nucleosynthesis and yields of low mass AGB stars at different metallicities (II): the FRUITY database
• Quantifying the uncertainties of chemical evolution studies. II. Stellar yields
• The Evolution of Isotope Ratios in the Milky Way Galaxy
• The s process in asymptotic giant branch stars of low metallicity and the composition of carbon-enhanced metal-poor stars
• Variability in red supergiant stars: pulsations, long secondary periods and convection noise
• Keplerian discs around post-AGB stars: a common phenomenon?
• s-Process Nucleosynthesis in Carbon Stars
• Evolution and nucleosynthesis of asymptotic giant branch stellar models of low metallicity
• Neutron Capture Elements in s-Process-Rich, Very Metal-Poor Stars
• s-Process in Low Metallicity Stars. I. Theoretical Predictions
• Post-AGB stars with hot circumstellar dust: binarity of the low-amplitude pulsators
• s-Process in Low Metallicity Stars. III. Individual analysis of CEMP-s and CEMP-s/r with AGB models
• More lead stars
• Optically visible post-AGB/RGB stars and young stellar objects in the Small Magellanic Cloud: candidate selection, spectral energy distributions and spectroscopic examination
• Heavy Element Nucleosynthesis in the Brightest Galactic Asymptotic Giant Branch stars
• Three carbon-enhanced metal-poor dwarf stars from the SDSS - Chemical abundances from CO^5BOLD 3D hydrodynamical model atmospheres
• Optically Visible Post-AGB Stars, Post-RGB Stars and Young Stellar Objects in the Large Magellanic Cloud
• Silicate features in Galactic and extragalactic post-AGB discs
• The WISE View of RV Tauri Stars
• A study of the s-process in the carbon-rich post-AGB stars IRAS06530-0213 and IRAS08143-4406 on the basis of VLT-UVES spectra
• The optically bright post-AGB population of the LMC
• Spectroscopic Analysis of Two Carbon Rich Post-AGB Stars
• Post-AGB stars in the SMC as tracers of stellar evolution: the extreme s-process enrichment of the 21 micrometer star J004441.04-732136.4
• The temperature and chronology of heavy-element synthesis in low-mass stars
• Detection of Keplerian dynamics in a disk around the post-AGB star AC Her
• A Spitzer Study of 21 and 30 Micron Emission in Several Galactic Carbon-rich Proto-Planetary Nebulae
• Post-AGB stars in the Magellanic Clouds and neutron-capture processes in AGB stars
• Detailed abundance study of four s-process enriched post-AGB stars in the Large Magellanic Cloud
• Chemical abundance study of two strongly s-process enriched post-AGB stars in the LMC: J051213.81-693537.1 and J051848.86-700246.9
• The lead discrepancy in intrinsically s-process enriched post-AGB stars in the Magellanic Clouds
• V453 Oph: a s-process enriched, but carbon-deficient RV Tauri star of low intrinsic metallicity
• An interferometric study of the post-AGB binary 89 Herculis I Spatially resolving the continuum circumstellar environment at optical and near-IR wavelengths with the VLTI, NPOI, IOTA, PTI, and the CHARA Array
• AGB nucleosynthesis in the Large Magellanic Cloud. Detailed abundance analysis of the RV Tauri star MACHO47.2496.8
• Identification of three new proto-Planetary Nebulae exhibiting the unidentified feature at 21 um
• IRAS08281-4850 and IRAS14325-6428: two A-type post-AGB stars with s-process enrichment

Cited by in corpus (29)

• Orbital properties of binary post-AGB stars
• Heavy-element yields and abundances of Asymptotic Giant Branch models with a Small Magellanic Cloud metallicity
• The orbits of subdwarf-B + main-sequence binaries: III. The period - eccentricity distribution
• Learning about the intermediate neutron-capture process from lead abundances
• The s process in AGB stars as constrained by a large sample of Barium stars
• Low-mass low-metallicity AGB stars as an efficient i-process site explaining CEMP-rs stars
• When binaries keep track of recent nucleosynthesis: The Zr - Nb pair in extrinsic stars as an s-process diagnostic
• s-Processing in AGB Stars Revisited. III. Neutron captures from MHD mixing at different metallicities and observational constraints
• Modelling depletion by re-accretion of gas from a dusty disc in post-AGB stars
• Disc-binary interactions in depleted post-AGB binaries
• APOGEE discovery of a chemically atypical star disrupted from NGC 6723 and captured by the Milky Way bulge
• Luminosities and masses of single Galactic Post-Asymptotic Giant Branch (Post-AGB) stars with distances from $Gaia$ EDR3: The revelation of an $s$-process diversity
• S stars and s-process in the Gaia era II. Constraining the luminosity of the third dredge-up with Tc-rich S stars
• Carbon stars with increased oxygen and nitrogen abundances: hydrostatic dust-free model atmospheres
• Variability in Protoplanetary Nebulae: IX. Evidence for Evolution in a Decade
• A study of carbon-rich post-AGB stars in the Milky Way to understand the production of carbonaceous dust from evolved stars
• Orbital and atmospheric parameters of two wide O-type subdwarf binaries: BD$-$11${}^{\mathrm{o}}$162 and Feige 80
• High-resolution spectroscopic analysis of four new chemically peculiar stars
• The NuGrid AGB Evolution and Nucleosynthesis Data Set
• Variability in Proto-Planetary Nebulae: VI. Multi-Telescope Light Curves Studies of Several Medium-Bright (V=13-15), Carbon-Rich Objects
• s-process Enriched Evolved Binaries in the Galaxy and the Magellanic Clouds
• s-process Enriched Post-AGB Star J003643.94-723722.1 in the SMC with an Extreme C/O Ratio and the First Precise Detection of Lead
• First models of s process in AGB stars of solar metallicity for the stellar evolutionary code ATON with a novel stable explicit numerical solver
• Exploring giant barium stars: ${}^{12}\mathrm{C}{/}^{13}\mathrm{C}$ ratio and elemental abundances of carbon, nitrogen, and oxygen
• Variability in Proto-Planetary Nebulae: VIII. A New Sample of Southern Hemisphere Objects
• Modeling the formation of the ${}^{13}$C neutron source in AGB stars
• Gaia DR2 and EDR3 data and evolutionary status of post-AGB stars with high radial velocities
• High-resolution optical spectroscopy of the post-AGB supergiant V340 Ser (=IRAS 17279$-$1119)
• CO second overtone line variability in three carbon-rich early post-AGB stage stars