Extrinsically metal-poor stars: photospheric chemical depletion in post-AGB/post-RGB stars in the Large Magellanic Cloud

Devika Kamath*, Hans Van Winckel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)
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Abstract

In this study, we use high-resolution optical spectra from the VLT + UVES to carry out a detailed stellar parameter and chemical abundance analysis for three newly identified depleted LMCpost-AGB/dusty post-RGB stars with circumstellar discs. Previously, only four luminous post-AGB stars in the Large Magellanic Cloud (LMC) have been observed to show signatures of chemical depletion. We find that the luminosities of the new depleted objects presented in this study are lower (1800 ≲ L/L ≲ 3300) than that of the previously known LMC depleted post-AGB stars (3000 ≲ to L/L ≲ 6500). This shows that chemical depletion is not only active in luminous post-AGB stars but also in stars with lower luminosities that have evolved-off lower on the AGB or evolved-off the RGB. Additionally, we compare the chemical depletion patterns of the LMC objects to their Galactic counterparts. We find a similar spread in the efficiency of depletion in both galaxies implying that the efficiency of photospheric depletion is independent of the initial metallicity of the host galaxy. While the spectral energy distributions of depleted post-AGB stars in the LMC and our Galaxy point to the presence of a likely circumstellar disc, we find that the stable circumstellar disc is needed but not a sufficient condition for acquiring the photospheric depletion abundance patterns. The efficiency of chemical depletion is complexly dependent on a suite of factors such as the effective temperature, luminosity, and the orbital properties of the binary systems.

Original languageEnglish
Pages (from-to)3524-3536
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume486
Issue number3
DOIs
Publication statusPublished - Jul 2019

Bibliographical note

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society, Volume 486, Issue 3, July 2019, Pages 3524–3536, https://doi.org/10.1093/mnras/stz1076. Copyright 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

Keywords

  • techniques: spectroscopic
  • stars: abundances
  • stars: AGB and post-AGB
  • stars: chemically peculiar
  • Galaxy: stellar content
  • Magellanic Clouds

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