HARPS丰度与Korg I：426颗红巨星的22种元素丰度
HARPS Abundances with Korg I: 22 Element Abundances for 426 Red Giant Stars
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中文总结 AI 辅助
该研究利用HARPS光谱和Korg代码确定426颗红巨星的多种参数及22种元素丰度，将元素整合到潜在变量模型，报告元素梯度，开发Korg管道，为化学演化提供经验约束和基准红巨星丰度测量。
中文摘要 AI 辅助
大型恒星巡天揭示了银河系的整体丰度结构，但小型高保真光谱样本提供了核合成深度的关键补充。我们旨在通过利用高质量光谱来获取丰度集合中编码的信息。我们使用HARPS光谱（R = 115,000）确定了426颗红巨星的（有效温度、表面重力、金属丰度、微观速度和旋转速度）以及22种元素丰度。恒星参数和逐线丰度通过现代光谱合成代码Korg获得。与文献比较显示总体一致性良好。金属丰度有0.1 dex的微小偏移，个别元素丰度存在差异。我们将22种元素整合到一个生成性的6参数潜在变量模型中，该模型能准确生成丰度。我们报告了相对于不同核合成家族选定元素的元素梯度，表明存在多个r过程产生位点。我们开发了Korg管道，可应用于高分辨率光谱的不同演化状态，提供精确目录以作为化学演化的经验约束和一组基准红巨星丰度测量。
英文摘要
Large stellar surveys have revealed the global abundance structure of the Milky Way, but small high-fidelity spectral samples offer a critical complement of nucleosynthetic depth. We aim to access the encoded information in an ensemble of abundances by leveraging highest-quality spectra. We used HARPS spectra (R=115,000) to determine (Teff, log(g), [M/H], vmic and vsini) and 22 element abundances (Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Fe, Ni, Zn, Sr, Y, Zr, Mo, Ba, La, Ce, Nd and Eu) for 426 red giant stars at a median internal precision of $\sim$0.02 dex evaluated from analysing repeat observations of a subset of stars. Stellar parameters and line-by-line abundances were obtained using the modern spectral synthesis code Korg -- the first time it has been used for HARPS. Comparisons with the literature reveal good overall agreement. A minor 0.1 dex offset in metallicity and specific discrepancies in individual element abundances are attributed to local thermal equilibrium assumptions and inaccuracies in atomic data. We show that 22 individual elements can be collapsed into a generative 6-parameter latent-variable model of shared enrichment patterns expressed in different per-star fractions; this model accurately generates the abundances with a median $χ_{reduced}^2 = 6$. We report element gradients with respect to selected elements from different nucleosynthetic families. These gradients are a measure of inter-element production efficiencies and indicate multiple r-process production sites. Our analysis shows that abundances occupy a low-dimensional subspace, but joint (gradient-based) information encodes nucleosynthetic signatures. We have developed a Korg-pipeline to apply across evolutionary states on high-resolution spectra to provide our precision catalogue to serve as empirical constraints on chemical evolution and as a set of benchmark red giant abundance measurements.
