Heavy-element yields and abundances of asymptotic giant branch models with a Small Magellanic Cloud metallicity

Amanda I. Karakas, Maria Lugaro, Marília Carlos, Borbála Cseh, Devika Kamath, D. A. García-Hernández

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Abstract

We present new theoretical stellar yields and surface abundances for asymptotic giant branch (AGB) models with a metallicity appropriate for stars in the Small Magellanic Cloud (SMC, Z = 0.0028, [Fe/H] ≈ -0.7). New evolutionary sequences and post-processing nucleosynthesis results are presented for initial masses between 1 and 7 M, where the 7 M is a super-AGB star with an O-Ne core. Models above 1.15 M become carbon rich during the AGB, and hot bottom burning begins in models M ≥ 3.75M. We present stellar surface abundances as a function of thermal pulse number for elements between C to Bi and for a selection of isotopic ratios for elements up to Fe and Ni (e.g. 12C/13C), which can be compared to observations. The integrated stellar yields are presented for each model in the grid for hydrogen, helium, and all stable elements from C to Bi.We present evolutionary sequences of intermediate-mass models between 4 and 7 M and nucleosynthesis results for three masses (M = 3.75, 5, and 7M) including s-process elements for two widely used AGB mass-loss prescriptions.We discuss our newmodels in the context of evolvedAGB and post-AGB stars in the SMCs, barium stars in our Galaxy, the composition of Galactic globular clusters including Mg isotopes with a similar metallicity to our models, and to pre-solar grains which may have an origin in metal-poor AGB stars.

Original languageEnglish
Pages (from-to)421-437
Number of pages17
JournalMonthly Notices of the Royal Astronomical Society
Volume477
Issue number1
DOIs
Publication statusPublished - 11 Jun 2018

Keywords

  • Abundances
  • Galaxies: Abundances
  • ISM: Abundances
  • Magellanic Clouds
  • Nuclear reactions
  • Nucleosynthesis
  • Stars: AGB and post-AGB

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