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http://hdl.handle.net/20.500.12386/31548
Title: | Magnetic-buoyancy-induced mixing in AGB stars: a theoretical explanation of the non-universal relation of [Y/Mg] to age | Authors: | MAGRINI, LAURA VESCOVI, Diego Casali, G. CRISTALLO, Sergio Viscasillas Vázquez, C. CESCUTTI, GABRIELE Spina, L. VAN DER SWAELMEN, Mathieu Benoit Jean RANDICH, Maria Sofia |
Issue Date: | 2021 | Journal: | ASTRONOMY & ASTROPHYSICS | Number: | 646 | First Page: | L2 | Abstract: | Context. Abundance ratios involving Y or other slow-neutron capture elements are routinely used to infer stellar ages. <BR /> Aims: We aim to explain the observed [Y/H] and [Y/Mg] abundance ratios of star clusters located in the inner disc with a new prescription for mixing in asymptotic giant branch (AGB) stars. <BR /> Methods: In a Galactic chemical evolution model, we adopted a new set of AGB stellar yields in which magnetic mixing was included. We compared the results of the model with a sample of abundances and ages of open clusters located at different Galactocentric distances. <BR /> Results: The magnetic mixing causes a less efficient production of Y at high metallicity. A non-negligible fraction of stars with super-solar metallicity is produced in the inner disc, and their Y abundances are affected by the reduced yields. The results of the new AGB model qualitatively reproduce the observed trends for both [Y/H] and [Y/Mg] versus age at different Galactocetric distances. <BR /> Conclusions: Our results confirm from a theoretical point of view that the relation between [Y/Mg] and stellar age cannot be `universal', that is, cannot be the same in every part of the Galaxy. It has a strong dependence on the star formation rate, on the s-process yields, and on their relation with metallicity, and it therefore varies throughout the Galactic disc. | URI: | http://hdl.handle.net/20.500.12386/31548 | URL: | https://www.aanda.org/articles/aa/full_html/2021/02/aa40115-20/aa40115-20.html http://arxiv.org/abs/2101.04429v1 |
ISSN: | 0004-6361 | DOI: | 10.1051/0004-6361/202040115 | Bibcode ADS: | 2021A&A...646L...2M | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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File | Description | Size | Format | |
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Magrini_2021_A&AL_646_2.pdf | Pdf editoriale | 1.17 MB | Adobe PDF | View/Open |
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