Zinc in the Sculptor dwarf spheroidal galaxy
Zinc in the Sculptor dwarf spheroidal galaxy
复制标题
玉夫座矮球状星系中的锌
DOI：
10.1051/0004-6361/201731158
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
M. Pettini
中科院分区：
文献类型：
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作者：
'Asa Sk'ulad'ottir;E. Tolstoy;S. Salvadori;V. Hill;M. Pettini
利用ESO VLT/FLAMES/GIRAFFE光谱，对玉夫座矮球状星系中约100颗红巨星分支（RGB）进行了Zn丰度测量。这是在银河系以外的恒星系统中单个锌丰度测量的最大样本。在观察到的金属丰度范围内，$-2.7\leq\text{[Fe/H]}\leq-0.9$，在玉夫座Zn丰度的一般趋势是类似的$\alpha$-元素。也就是说，在低金属丰度下，[Zn/Fe]的超太阳丰度比随着[Fe/H]的增加而降低，最终达到太阳下的值。然而，在Sculptor的较高金属丰度处，$\text{[Fe/H]}\gtrsim-1.8$，我们发现了一个显著的散点，$-0.8\lesssim\text{[Zn/Fe]}\lesssim+0.4$，这在任何$\alpha$-元素中都没有看到。我们的研究结果是一致的，与以前的观测数量有限的恒星在玉夫座和其他矮星系。这些结果表明，锌有一个复杂的核合成的起源，行为既不完全像一个$\alpha$-也不是一个铁峰元素。
From ESO VLT/FLAMES/GIRAFFE spectra, abundance measurements of Zn have been made in $\approx$100 individual red giant branch (RGB) stars in the Sculptor dwarf spheroidal galaxy. This is the largest sample of individual Zn abundance measurements within a stellar system beyond the Milky Way. In the observed metallicity range, $-2.7\leq\text{[Fe/H]}\leq-0.9$, the general trend of Zn abundances in Sculptor is similar to that of $\alpha$-elements. That is, super-solar abundance ratios of [Zn/Fe] at low metallicities, which decrease with increasing [Fe/H], eventually reaching subsolar values. However, at the higher metallicities in Sculptor, $\text{[Fe/H]}\gtrsim-1.8$, we find a significant scatter, $-0.8\lesssim\text{[Zn/Fe]}\lesssim+0.4$, which is not seen in any $\alpha$-element. Our results are consistent with previous observations of a limited number of stars in Sculptor and in other dwarf galaxies. These results suggest that zinc has a complex nucleosynthetic origin, behaving neither completely like an $\alpha$- nor an iron-peak element.