Evolution of the distribution of neutron exposures in the Galaxy disc: An analytical model |
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Authors: | Wenyuan Cui Weijuan Zhang Bo Zhang |
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Institution: | (1) Department of Physics, Hebei Normal University, Shijiazhuang, 050 016, P. R. China;(2) National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100 012, P. R. China;(3) Graduate School of Chinese Academy of Sciences, Beijing, 100 049, P. R. China |
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Abstract: | In this work, based on the analytical model with delayed production approximation developed by Pagel & Tautvaišienė (1995)
for the Galaxy, the analytic solutions of the distribution of neutron exposures of the Galaxy (hereafter NEG) are obtained.
The present results appear to reasonably reproduce the distribution of neutron exposures of the solar system (hereafter NES).
The strong component and the main component of the NES are built up in different epochs. Firstly, the strong component is
produced by the s-process nucleosynthesis in the metal-poor AGB stars, starting from Fe/H] ≈ −1.16 to Fe/H] ≈ −0.66, corresponding
to the time interval 1.06 < t < 2.6 Gyr. Secondly, the main component is produced by the s-process in the galactic disk AGB stars, starting from Fe/H]
≈ −0.66 to Fe/H] ≈ 0, corresponding to the time interval t > 2.6 Gyr. The analytic solutions have the advantage of an understanding of the structure and the properties of the NEG.
The NEG is believed to be an effective tool to study the s-process element abundance distributions in the Galaxy at different
epochs and the galactic chemical evolution of the neutron-capture elements. |
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Keywords: | Nucleosynthesis neutron exposures abundances stars: AGB stars: low-mass stars galaxy: evolution |
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