A window on the efficiency of the s-process in AGB stars: chemical abundances of n-capture elements in the planetary nebula NGC 3918
arXiv:1510.04548
Abstract
The chemical content of the planetary nebula NGC 3918 is investigated through deep, high-resolution (R~40000) UVES at VLT spectrophotometric data. We identify and measure more than 750 emission lines, making ours one of the deepest spectra ever taken for a planetary nebula. Among these lines we detect very faint lines of several neutron-capture elements (Se, Kr, Rb, and Xe), which enable us to compute their chemical abundances with unprecedented accuracy, thus constraining the efficiency of the s-process and convective dredge-up in the progenitor star of NGC 3918.
4 pages, 5 figures, 1 table. To appear in the Memorie della Società Astronomica Italiana. Proceedings of the EWASS 2015 Special Session "AGB stars: a key ingredient in the understanding and interpretation of stellar populations"