Detailed Iron-peak Element Abundances in Three Very Metal-poor Stars
Detailed Iron-peak Element Abundances in Three Very Metal-poor Stars
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DOI：
10.3847/1538-4357/ab6aa9
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发表时间：
2020-01
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影响因子：
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通讯作者：
J. Cowan;C. Sneden;I. Roederer;J. Lawler;E. A. Hartog;J. Sobeck;A. Boesgaard
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作者：
J. Cowan;C. Sneden;I. Roederer;J. Lawler;E. A. Hartog;J. Sobeck;A. Boesgaard
我们在三颗金属非常贫乏（[Fe/H] ≈ -3）的恒星：BD+03o740、BD−13o3442 和 CD−33o1173 中获得了 Fe 族元素 Sc 到 Zn (Z = 21–30) 的新详细丰度。收集了波长范围 2300–3050 Å 的高分辨率紫外哈勃太空望远镜/太空望远镜成像摄谱仪光谱，并辅以各种光学阶梯光谱。该分析采用了除铜和锌之外的所有铁族元素的许多中性和电离物质的最新实验室原子数据。对大样本光谱调查中钪、钛和钒丰度的详细检查表明，它们在 [Fe/H] ≤ -2 的恒星中呈正相关。 BD+03o740、BD−13o3442、CD−33o1173 和 HD 84937（在本系列的前一篇论文中研究）中这些元素的丰度符合这些趋势，并且位于相关性的高端。六种元素具有可检测到的中性和电离特征，并且通常它们的丰度相当一致。对于 Cr，我们发现中性物质（[Cr i/Fe] 平均值 = +0.01）和电离物质（[Cr ii/Fe] 平均值 = +0.08）之间的丰度差异极小，这与过去的大多数研究不同。突出的例外是 Co，其中中性物质表明显着过量（[Co i/H] 平均值 = -2.53），而电离物质则没有看到这种增强（[Co ii/H] 平均值 = -2.93）。这些新的恒星丰度，特别是钪、钛和钒之间的相关性，表明应该重新审视早期大质量贫金属恒星的元素生产模型。
We have obtained new detailed abundances of the Fe-group elements Sc through Zn (Z = 21–30) in three very metal-poor ([Fe/H] ≈ −3) stars: BD+03o740, BD−13o3442, and CD−33o1173. High-resolution ultraviolet Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra in the wavelength range 2300–3050 Å were gathered, and complemented by an assortment of optical echelle spectra. The analysis featured recent laboratory atomic data for a number of neutral and ionized species for all Fe-group elements except Cu and Zn. A detailed examination of scandium, titanium, and vanadium abundances in large-sample spectroscopic surveys indicates that they are positively correlated in stars with [Fe/H] ≤ −2. The abundances of these elements in BD+03o740, BD−13o3442, CD−33o1173, and HD 84937 (studied in a previous paper of this series) are in accord with these trends and lie at the high end of the correlations. Six elements have detectable neutral and ionized features, and generally their abundances are in reasonable agreement. For Cr we find only minimal abundance disagreement between the neutral (mean of [Cr i/Fe] = +0.01) and ionized species (mean of [Cr ii/Fe] = +0.08), unlike most studies in the past. The prominent exception is Co, for which the neutral species indicates a significant overabundance (mean of [Co i/H] = −2.53), while no such enhancement is seen for the ionized species (mean of [Co ii/H] = −2.93). These new stellar abundances, especially the correlations among Sc, Ti, and V, suggest that models of element production in early high-mass metal-poor stars should be revisited.