New Constraints on the Major Neutron Source in Low-mass AGB Stars

Journal
Date Issued
2018
Author(s)
Liu, Nan
•
Gallino, Roberto
•
•
Bisterzo, Sara
•
Davis, Andrew M.
•
Trappitsch, Reto
•
Nittler, Larry R.
DOI
Abstract
We compare updated Torino postprocessing asymptotic giant branch (AGB) nucleosynthesis model calculations with isotopic compositions of mainstream SiC dust grains from low-mass AGB stars. Based on the data-model comparison, we provide new constraints on the major neutron source, 13C(α, n)16O in the He-intershell, for the s-process. We show that the literature Ni, Sr, and Ba grain data can only be consistently explained by the Torino model calculations that adopt the recently proposed magnetic-buoyancy-induced 13C-pocket. This observation provides strong support to the suggestion of deep mixing of H into the He-intershell at low 13C concentrations as a result of efficient transport of H through magnetic tubes.
Volume
865
Issue
2
Start page
112
Uri
Url
Issn Identifier
0004-637X
Ads BibCode
2018ApJ...865..112L
Rights
open.access
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