利用Gaia-ESO疏散星团研究银盘的化学-动力学分层
Chemo-dynamical stratification of the Galactic disc using \emph{Gaia}-ESO open clusters
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中文总结 AI 辅助
本研究利用Gaia-ESO巡天与Gaia DR3数据，分析疏散星团，揭示银盘星团轨道与化学性质随年龄的系统变化，明确银盘化学-动力学结构的年龄依赖性。
中文摘要 AI 辅助
理解银盘的形成与演化需要追溯恒星化学与轨道结构随时间的耦合演化。疏散星团作为具有精确年龄、距离和化学性质的同代恒星群体，为该研究提供了有力的基准。本研究旨在表征银盘与年龄相关的化学-动力学结构，并探究疏散星团如何随年龄分布在动力学相空间中。我们结合Gaia-ESO巡天的均匀化学丰度数据与Gaia DR3的相空间信息，分析了一个银盘疏散星团样本，将星团年龄与轨道参数及作用量结合，研究其在过去约40亿年中在动力学相空间的分布情况。研究发现，具有相似化学性质的星团占据作用量空间的连贯区域，而其轨道结构则表现出明显的年龄依赖性：径向偏移量和轨道偏心率随年龄系统增大，表明年老星团群体的轨道构型日益多样化；[Fe/H]-Rg关系的离散度也随年龄增加，这与长期重分布、幸存偏差及动力学上不同的外盘星团群体共同作用的结果一致。此外，年老星团达到更大的垂直振幅和垂直作用量，揭示了面内与垂直轨道结构之间存在耦合但各向异性的演化。疏散星团是银盘化学-动力学结构的精确、年龄分辨示踪体，本研究结果揭示了星团群体轨道与化学性质随年龄的系统变化，与过去几十亿年间长期演化、轨道重分布及环境依赖的星团幸存效应的共同作用相符。
英文摘要
Understanding how the Milky Way disc assembled and evolved requires tracing the coupled evolution of stellar chemistry and orbital structure over time. Open clusters, as coeval stellar populations with well-constrained ages, distances, and chemical properties, provide powerful benchmarks for this purpose. We aim to characterise the age-dependent chemo-dynamical structure of the Galactic disc and to investigate how open clusters populate dynamical phase space as a function of age. We analysed a sample of Galactic open clusters using homogeneous chemical abundances from the Gaia-ESO Survey together with Gaia DR3 phase-space information. Combining cluster ages with orbital parameters and actions, we examined how clusters populate dynamical phase space over the last ~4 Gyr. We find that clusters with similar chemical properties occupy coherent regions of action space, while their orbital structure shows a clear dependence on age. Radial excursions and orbital eccentricities broaden systematically toward older ages, indicating increasingly diverse orbital configurations in the older cluster population. The dispersion in the [Fe/H]-Rg relation also increases with age, consistent with a combination of secular redistribution, survival bias, and dynamically distinct outer-disc populations. In addition, older clusters reach larger vertical amplitudes and vertical actions, revealing a coupled but anisotropic evolution between in-plane and vertical orbital structure. Open clusters provide precise, age-resolved tracers of the chemo-dynamical structure of the Galactic disc. Our results reveal systematic age-dependent variations in the orbital and chemical properties of the cluster population, consistent with the combined effects of secular evolution, orbital redistribution, and environmentally dependent cluster survival over the last few Gyr.
