Open clusters are groups of young stars that formed nearly simultaneously from the same molecular cloud. Because their member stars share a common age, distance, and initial chemical composition, open clusters serve as ideal laboratories for studying the initial mass function, stellar evolution, and chemical abundances. In recent years, spectroscopic surveys of open clusters have revealed chemical abundance gradients across the Milky Way. In particular, clusters located in the inner regions of the Galaxy tend to show higher abundances of neutron-capture elements, while those in the outer regions exhibit lower abundances of these elements. We investigated whether the abundances of neutron-capture elements differ between open clusters that have similar present-day Galactocentric distances but originated in different regions of the Galaxy. We measured the abundances of neutron-capture elements – Y, Zr, Ba, La, Ce, Pr, Nd, Sm, and Eu – in dwarfs belonging to the open clusters Pleiades, Hyades, and Praesepe. Archival high-resolution spectra obtained with the HIRES spectrograph on the Keck Telescope were used for the analysis. For each star, we determined the effective temperature, surface gravity, microturbulence velocity, and [Fe/H]. Based on these atmospheric parameters, we derived the abundances of the neutron-capture elements for a total of 32 dwarfs. There are basically no significant differences in the chemical composition among clusters, but there may be some differences. The dwarfs in the Hyades and Praesepe clusters were found to have similar abundances of neutron-capture elements. For many of these elements, the [X/Fe] in Hyades and Praesepe were 0.06 to 0.36 dex lower than those in the Pleiades. In contrast, the [X/H] were 0.03 to 0.24 dex higher in Hyades and Praesepe for the majority of the elements analyzed. The [Fe/H] of the Hyades and Praesepe clusters are higher than that of the Pleiades, suggesting a significant enrichment of iron from Type Ia supernovae at the birth sites of Hyades and Praesepe. In contrast, the higher abundances of neutron-capture elements relative to hydrogen indicate substantial contributions from neutron star mergers and/or asymptotic giant branch (AGB) stars in those regions. This chemical enrichment cannot be explained by age differences alone, as the Hyades and Praesepe are older than the Pleiades. These findings support the idea that chemical composition in the Milky Way can vary between different birth environments, even at similar Galactocentric distances.
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