论文标题
银河中心的详细丰度：金属丰富的α增强恒星种群的证据
Detailed abundances in the Galactic center: Evidence of a metal-rich alpha-enhanced stellar population
论文作者
论文摘要
我们提出了一项详细的研究，该研究对银河中心的20 M巨人组成，其中15个被证实在核星群中。作为对照样本，我们还观察到具有类似恒星参数的银河系磁盘中的7个巨人。使用NIRSPEC镜头在K频段的Keck II望远镜上以r = 23,000的分辨能力观察到所有27颗恒星。我们报告了银河中心的恒星的第一个硅丰度趋势与[Fe/H]。在发现磁盘/凸起的趋势趋势下，我们发现[Si/fe]在超极金属率上得到了增强。我们推测可能的丰富方案以解释这种趋势。但是，样本量很小，结果需要通过对硅和其他\ textalpha元素的其他测量来确认结果。我们还得出了[Fe/H]的新分布，并在[Fe/H] =+0.5 Dex上找到最富含金属的恒星，这证实了我们较早的结论，即银河中心没有具有极端化学成分的恒星。
We present a detailed study of the composition of 20 M giants in the Galactic center with 15 of them confirmed to be in the Nuclear Star Cluster. As a control sample we have also observed 7 M giants in the Milky Way Disk with similar stellar parameters. All 27 stars are observed using the NIRSPEC spectograph on the KECK II telescope in the K-band at a resolving power of R=23,000. We report the first silicon abundance trends versus [Fe/H] for stars in the Galactic center. While finding a disk/bulge like trend at subsolar metallicities, we find that [Si/Fe] is enhanced at supersolar metallicities. We speculate on possible enrichment scenarios to explain such a trend. However, the sample size is modest and the result needs to be confirmed by additional measurements of silicon and other \textalpha-elements. We also derive a new distribution of [Fe/H] and find the most metal rich stars at [Fe/H]=+0.5 dex, confirming our earlier conclusions that the Galactic center hosts no stars with extreme chemical composition.
