We present a new abundance analysis of the intermediate age Galactic open cluster NGC 3680, based on high resolution, high signal-to-noise VLT/UVES spectroscopic data. Several element abundances are presented for this cluster for the first time, but most notably we derive abundances for the light and heavy s-process elements Y, Ba, La, and Nd. The serendipitous measurement of the rare-earth r-process element Gd is also reported. This cluster exhibits a significant enhancement of Na in giants as compared to dwarfs, which may be a proxy for an O to Na anti-correlation as observed in Galactic globular clusters but not open clusters. We also observe a step-like enhancement of heavy s-process elements towards higher atomic number, contrary to expectations from AGB nucleosynthesis models, suggesting that the r-process played a significant role in the generation of both La and Nd in this cluster
@article{arxiv.1203.1085,
title = {Elemental abundances of intermediate age open cluster NGC 3680},
author = {A. W. Mitschang and G. M. De Silva and D. B. Zucker},
journal= {arXiv preprint arXiv:1203.1085},
year = {2015}
}
Comments
8 pages, 6 figures, accepted for publication in MNRAS