Neutron-Capture Elements in the Very Metal Poor Star HD 122563
Neutron-Capture Elements in the Very Metal Poor Star HD 122563
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DOI：
10.1086/503195
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发表时间：
2006-02
期刊：
影响因子：
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通讯作者：
S. Honda;W. Aoki;Y. Ishimaru;S. Wanajo;S. Ryan
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文献类型：
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作者：
S. Honda;W. Aoki;Y. Ishimaru;S. Wanajo;S. Ryan
我们获得了高分辨率，高信噪比（S/N）光谱的非常贫金属星星HD 122563与斯巴鲁望远镜高色散光谱仪。先前的研究表明，该天体拥有过量的轻中子捕获元素，而其重元素的丰度非常低。在我们的光谱中，覆盖了该天体的3070-4780 nm，检测到19种中子捕获元素，其中包括7种首次在该星星中发现的元素（Nb，Mo，Ru，Pd，Ag，Pr和Sm）。给出了包括Th在内的其他五种元素的上限。从Sr到Yb，丰度随原子序数的变化呈现逐渐减小的趋势，这与r过程元素过剩的恒星有很大的不同。中子俘获元素的丰度模式提供了新的强有力的约束模型的核合成负责非常贫金属的轻中子俘获元素过剩的恒星，但没有增强重的。
We obtained high-resolution, high signal-to-noise ratio (S/N) spectroscopy for the very metal poor star HD 122563 with the Subaru Telescope High Dispersion Spectrograph. Previous studies have shown that this object has excesses of light neutron-capture elements, while its abundances of heavy ones are very low. In our spectrum, which covers 3070-4780 Å of this object, 19 neutron-capture elements have been detected, including seven for the first time in this star (Nb, Mo, Ru, Pd, Ag, Pr, and Sm). Upper limits are given for five other elements including Th. The abundance pattern shows a gradually decreasing trend, as a function of atomic number, from Sr to Yb, which is quite different from those in stars with excesses of r-process elements. This abundance pattern of neutron-capture elements provides new strong constraints on the models of nucleosynthesis responsible for the very metal poor stars with excesses of light neutron-capture elements but without enhancement of heavy ones.