s-process Enriched Evolved Binaries in the Galaxy and the Magellanic Clouds

Abstract

Post-asymptotic giant branch stars (post-AGB) in binary systems, with typical orbital periods between ~100 to ~1000 days, result from a poorly understood interaction that terminates their precursory AGB phase. The majority of these binaries display a photospheric anomaly called 'chemical depletion', thought to arise from an interaction between the circumbinary disc and the post-AGB star, leading to the reaccretion of pure gas onto the star, devoid of refractory elements due to dust formation. In this paper, we focus on a subset of chemically peculiar binary post-AGBs in the Galaxy and the Magellanic Clouds (MCs) whose high-resolution optical spectroscopic study revealed a carbon and s-process enrichment, contrary to the commonly observed photospheric chemical depletion. Using spectral energy distribution (SED) fitting and period-luminosity-colour (PLC) relation methods, we determine the luminosity of the targets ($2700-8300L_{\odot }$), which enables confirmation of their evolutionary phase and estimation of initial masses (as a function of metallicity) ($1-2.5M_{\odot }$). In conjunction with predictions from dedicated ATON stellar evolutionary models, our results indicate a predominant intrinsic enrichment of carbon and s-process elements in our binary post-AGB targets. We qualitatively rule out extrinsic enrichment and inherited s-process enrichment from the host galaxy as plausible explanations for the observed overabundances. Our chemically peculiar subset of intrinsic carbon and s-process enriched binary post-AGBs also hints at potential variation in the efficiency of chemical depletion between stars with C-rich and O-rich circumbinary disc chemistries. However, critical observational studies of circumbinary disc chemistry are necessary to address gaps in our current understanding of disc-binary interactions inducing chemical depletion in binary post-AGB systems.

arXiv comment25 pages, 14 figures, 7 tables

References in corpus (59)

• The chemical composition of the Sun
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• The VizieR database of Astronomical Catalogues
• Elemental Abundance Survey of The Galactic Thick Disk
• The s Process: Nuclear Physics, Stellar Models, Observations
• The Chemical Compositions of Galactic Disk F and G Dwarfs
• The Dawes Review 2: Nucleosynthesis and stellar yields of low and intermediate-mass single stars
• alpha-, r-, and s-process element trends in the Galactic thin and thick disks
• Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec
• Nucleosynthesis and mixing on the Asymptotic Giant Branch. III. Predicted and observed s-process abundances
• The Rise of the s-Process in the Galaxy
• Modern stellar spectroscopy caveats
• Electron-capture supernovae as the origin of elements beyond iron
• New Period-Luminosity and Period-Color Relations of Classical Cepheids: I. Cepheids in the Galaxy
• New Optical Reddening Maps of the Large and Small Magellanic Clouds
• s-Process Nucleosynthesis in Carbon Stars
• The Hamburg/ESO R-process Enhanced Star survey (HERES) III. HE 0338-3945 and the formation of the r+s stars
• A White Dwarf catalogue from Gaia-DR2 and the Virtual Observatory
• Post-AGB stars with hot circumstellar dust: binarity of the low-amplitude pulsators
• Chemical abundances in LMC stellar populations. II. The bar sample
• Orbital properties of binary post-AGB stars
• Barium & related stars and their white-dwarf companions I. Giant stars
• Optically visible post-AGB/RGB stars and young stellar objects in the Small Magellanic Cloud: candidate selection, spectral energy distributions and spectroscopic examination
• 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
• The Large Magellanic Cloud and the Distance Scale
• 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
• Depletion in post-AGB stars with a dusty disc. II
• The optically bright post-AGB population of the LMC
• The VMC Survey. XIII. Type II Cepheids in the Large Magellanic Cloud
• 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
• A Comparison of the Chemical Evolutionary Histories of the Galactic Thin Disk and Thick Disk Stellar Populations
• Heavy elements in Globular Clusters: the role of AGB stars
• Detailed homogeneous abundance studies of 14 Galactic s-process enriched post-AGB stars: In search of lead (Pb)
• A population of transition disks around evolved stars: Fingerprints of planets? Catalog of disks surrounding Galactic post-AGB binaries
• The Linearity of the Wesenheit function for the Large Magellanic Cloud Cepheids
• A helium-flash-induced mixing event can explain the lithium abundances of red clump stars
• Jet creation in post-AGB binaries: the circum-companion accretion disc around BD+46${}^{\circ }$442
• 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
• Chemical depletion in the Large Magellanic Cloud: RV Tauri stars and the photospheric feedback from their dusty discs
• Barium and related stars, and their white-dwarf companions. III. The masses of the white dwarfs
• V453 Oph: a s-process enriched, but carbon-deficient RV Tauri star of low intrinsic metallicity
• The chemical DNA of the Magellanic Clouds -- I. The chemical composition of 206 Small Magellanic Cloud red giant stars
• The structure of jets launched from post-AGB binary systems
• 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
• AGB nucleosynthesis in the Large Magellanic Cloud. Detailed abundance analysis of the RV Tauri star MACHO47.2496.8
• The evolutionary nature of RV Tauri stars in the SMC and LMC
• Discovery of technetium- and niobium-rich S stars: the case for bitrinsic stars
• Detection of elements beyond the Ba-peak in VLT+UVES spectra of post-AGB stars
• Synthesis of thorium and uranium in asymptotic giant branch stars
• Discovery of a Metal-poor, Luminous Post-AGB Star that Failed the Third Dredge-up
• Understanding dust production and mass loss on the AGB phase using post-AGB stars in the Magellanic Clouds
• Jet parameters for a diverse sample of jet-launching post-AGB binaries
• Spectroscopic study of Ba and CEMP-s stars: Mass distribution of AGB progenitors
• Distance to the SMC from eclipsing binaries
• The evolutionary status of the bright high-latitude supergiant HD190390

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