T-GEX 项目. II. UV 明亮 FGK 恒星的时间-化学-动力学特征
The T-GEX project. II. Chrono-chemo-dynamic signatures of UV-bright FGK stars
- Pontificia Universidad Católica de Chile（智利天主教 Pontificia 大学）
- Polish Academy of Sciences（波兰科学院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过比较37颗T-GEX恒星的年龄、化学丰度和轨道，发现UV发射分组与化学增丰模式相关，支持高能核坍缩增丰及更内形成区域，但无单一因果路径。
AI中文摘要：
我们比较了 37 颗具有强 (G1)、正常 (G2) 和中等 (G3) UV 发射的 T-GEX 恒星的年龄、化学丰度、银心轨道和推断的诞生环境。这些组显示出不同的相关结构：在 G1 中，UV 颜色与化学和轨道量相关；G2 具有最多数量的显著（反）相关；而在 G3 中，没有 UV 颜色相关达到所采用的阈值。大多数恒星具有顺行盘状轨道，而两个类晕天体都属于 G2。这些组在 [Mg/Fe]-[Fe/H] 平面上重叠，但 G1 向较低的 [Fe/H] 和较高的 [Mg/Fe] 偏移。在 18 个可能的薄盘成员中，G3 的中位诞生半径小于 G2（5.70 对比 8.10 kpc），尽管它们的中位引导半径 ($\langle R_g \rangle$；8.23 对比 8.25 kpc) 几乎相同。所有五颗 G1 恒星相对于 Fe 都富 Ti，其中四颗结合了增强的 Co 与相对较低的 Mn，在某些情况下还有 Cr。在 G3 中出现了相关但不完整的模式，而 G2 中一些恒星的 Co 增强并未重现这种联合特征。UV 定义的组是异质的，并不对应于独特的银河系组成部分。α 增强（可能是厚盘成员）、正的 Ti 比率以及 Cr-Mn-Fe-Co-Ni 化学丰度模式（在 G1 中最清晰，但在 G3 中以相关形式存在）的汇聚支持了高能核坍缩（即超新星）对某些 UV 过量恒星诞生物质的增丰。此外，较小的 G3 诞生半径（对于银河系薄盘中的那些）表明更靠内的形成区域，并提供了与旋涡星系核球中 UV 明亮恒星群体的可能空间联系。这两项结果都没有建立单一的因果路径。混合依赖的金属线遮蔽是否将这种增丰与 UV 发射联系起来，需要定制的光谱建模。
英文摘要：
We compare the ages, chemical abundances, Galactic orbits, and inferred birth environments of 37 T-GEX stars with strong (G1), normal (G2), and intermediate (G3) UV emission. The groups show distinct correlation structures: UV colours correlate with chemical and orbital quantities in G1; G2 has the largest number of significant (anti-)correlations; and no UV-colour correlation reaches the adopted threshold in G3. Most stars have prograde disc-like orbits, while both halo-like objects belong to G2. The groups overlap in the [Mg/Fe]-[Fe/H] plane, but G1 is shifted towards lower [Fe/H] and higher [Mg/Fe]. Among the 18 probable thin-disc members, G3 has a smaller median birth radius than G2 (5.70 versus 8.10 kpc), despite their nearly identical median guiding radii ($\langle R_g \rangle$; 8.23 versus 8.25 kpc). All five G1 stars are Ti-enriched compared to Fe, and four combine enhanced Co with comparatively low Mn and, in some cases, Cr. A related but less complete pattern occurs in G3, whereas Co enhancement in some G2 stars does not reproduce the joint signature. The UV-defined groups are heterogeneous and do not correspond to unique Galactic components. The convergence of $α$-enhancement (likely thick disc members), positive Ti ratios, and the Cr-Mn-Fe-Co-Ni chemical abundance pattern (clearest in G1 but present in related form in G3) supports high-energy core-collapse (i.e. hypernovae) enrichment of the natal material of some UV-excess stars. Additionally, the smaller G3 birth radii (for those in the Galactic thin disc) indicate more inward formation regions and provide a possible spatial link to UV-bright stellar populations in the bulges of spiral galaxies. Neither result establishes a single causal pathway. Whether mixture-dependent metal-line blanketing connects this enrichment to the UV emission requires tailored spectral modelling.
