https://doi.org/10.1140/epja/s10050-026-01837-0
Regular Article - Theoretical Physics
Predictions from s-process AGB models of the isotopic variations of zirconium and neodymium for comparison to bulk meteorites
1
Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences, Konkoly Thege M. út 15-17, 1121, Budapest, Hungary
2
CSFK, MTA Centre of Excellence, Konkoly Thege Miklós út 15-17, 1121, Budapest, Hungary
3
Institute of Physics, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, 1117, Budapest, Hungary
4
School of Physics and Astronomy, Monash University, 3800, Clayton, VIC, Australia
5
Centre for Astrophysics & Supercomputing, Swinburne University of Technology, 3122, Hawthorn, VIC, Australia
6
Department of Experimental Physics, Institute of Physics, University of Szeged, Dóm tér 9, 6720, Szeged, Hungary
7
Department of Earth and Planetary Sciences, Institute of Geochemistry and Petrology, ETH Zürich, Zurich, Switzerland
8
MTA-ELTE Lendület “Momentum” Milky Way Research Group, Szent Imre H. u. 112, 9700, Szombathely, Hungary
a
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Received:
28
November
2025
Accepted:
14
March
2026
Published online:
20
April
2026
Abstract
Bulk meteoritic data show isotopic variability of slow-neutron-capture (s-process) origin in several elements heavier than Fe. One peculiar feature is that the lighter s-process elements (e.g., Zr and Mo) present larger anomalies than the heavier s-process elements (e.g., Nd and W). To address this observation, we compared Zr and Nd data to model predictions of the s-process abundances at the surface of low-mass asymptotic giant branch (AGB) stars of initial metallicity from solar to twice solar. We found that the relative magnitude of the isotopic variability between these two elements can be matched by models of AGB stars of super-solar metallicity. The match is favoured by stronger convective overshoot, leading to a deeper dredge-up of the H-rich envelope into the He-rich region, and/or a smaller (
half than standard) mass of the region rich in the 
C nuclei that produce free neutrons via the C(
n)
O reaction. We conclude that nucleosynthesis in AGB stars can match the difference in the magnitude of the bulk meteoritic variations in Zr and Nd, provided that super-solar metallicity stars are the original site of these signatures. The AGB stars that produced such variations could have belonged to the current population of old, super-solar metallicity stars seen in the galactic solar neighbourhood.
Communicated by Maria Borge.
© The Author(s) 2026
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