Modeling the formation of the ${}^{13}$C neutron source in AGB stars

Abstract

A major source of uncertainty in AGB models is the partial-mixing process of hydrogen, required for the formation of the so-called ${}^{13}$C pocket. Among the attempts to derive a self-consistent treatment of this physical process, there are 2D and 3D simulations of magnetic buoyancy. The ${}^{13}$C pocket resulting from mixing induced by magnetic buoyancy extends over a region larger than those so far assumed, showing an almost flat ${}^{13}$C distribution and a negligible amount of ${}^{14}$N. Recently, it has been proved to be a good candidate to match the records of isotopic abundance ratios of $s$-elements in presolar SiC grains. However, up to date such a magnetic mixing has been applied in post-process calculations only, being never implemented in a stellar evolutionary code. Here we present new stellar models, performed with the 1-d hydrostatic FUNS evolutionary code, which include magnetic buoyancy. We comment the resulting $s$-process distributions and show preliminary comparisons to spectroscopic observations and pre-solar grains measurements.

arXiv comment4 pages, 2 figures, NPA IX proceedings. Accepted in JPCS

References in corpus (15)

• Evolution, nucleosynthesis and yields of low mass AGB stars
• Evolution, nucleosynthesis and yields of low mass AGB stars at different metallicities (II): the FRUITY database
• s-Process Nucleosynthesis in Carbon Stars
• Barium Isotopic Composition of Mainstream Silicon Carbides from Murchison: Constraints for s-Process Nucleosynthesis in AGB Stars
• $s$-Processing in AGB Stars Revisited. II. Enhanced ${}^{13}$C Production Through MHD-Induced Mixing
• 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
• Application of a Theory and Simulation based Convective Boundary Mixing model for AGB Star Evolution and Nucleosynthesis
• Correlated Strontium and Barium Isotopic Compositions of Acid-Cleaned Single Silicon Carbides from Murchison
• MHD and deep mixing in evolved stars. 1. 2D and 3D analytical models for the AGB
• The importance of the 13C(alpha,n)16O reaction in Asymptotic Giant Branch stars
• Detailed homogeneous abundance studies of 14 Galactic s-process enriched post-AGB stars: In search of lead (Pb)
• The chemical composition of carbon stars: The R-type stars
• On the Origin of the Early Solar System Radioactivities. Problems with the AGB and Massive Star Scenarios
• Chemical abundance study of two strongly s-process enriched post-AGB stars in the LMC: J051213.81-693537.1 and J051848.86-700246.9
• s-Processing from MHD-induced mixing and isotopic abundances in presolar SiC grains

Cited by in corpus (1)

• The carbon star mystery: forty years later