Elemental abundances of intermediate-age open cluster NGC 3680
Abstract
We present a new abundance analysis of the intermediate-age Galactic open cluster NGC 3680, based on high-resolution, high signal-to-noise ratio 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 anticorrelation 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 asymptotic giant branch nucleosynthesis models, suggesting that the r process played a significant role in the generation of both La and Nd in this cluster.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2012
- DOI:
- 10.1111/j.1365-2966.2012.20866.x
- arXiv:
- arXiv:1203.1085
- Bibcode:
- 2012MNRAS.422.3527M
- Keywords:
-
- stars: abundances;
- open clusters and associations: general;
- open clusters and associations: individual: NGC 3680;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 8 pages, 6 figures, accepted for publication in MNRAS