AI 中文总结
利用LAMOST亚巨星样本，通过正向建模发现轻元素和α元素内在丰度弥散小（≲0.05 dex），中子俘获元素弥散大（≳0.1 dex），且不能用单一示踪剂解释，凸显其化学标记潜力。
AI 中文摘要
在相似年龄和金属丰度的恒星中，元素丰度的弥散反映了其诞生环境的化学不均匀性，使得丰度弥散成为化学标记研究银河系形成与演化的关键可观测量。利用从LAMOST低分辨率光谱中推导出的具有精确年龄和元素丰度的大样本亚巨星恒星，我们研究了太阳邻域（7 < R < 10 kpc）附近低-α薄盘的内在化学丰度弥散。我们针对所关注的19种元素中的每一种，将丰度比[X/Fe]建模为年龄、[Fe/H]和[Mg/Fe]的函数，并通过正向建模技术推导出内在弥散。我们的结果证实了先前的发现，即对于轻元素（C、Al）、α元素（O、Mg、Si、Ca、Ti）和铁峰元素（Mn、Ni），内在弥散很小，通常≲0.05 dex。对M67的专门分析也得出了这些元素类似的较小弥散值，这意味着仅凭轻元素丰度提供的区分能力有限。相比之下，中子俘获元素表现出明显更大的弥散，通常≳0.1 dex，显著大于M67成员星的弥散（~0.07 dex）。特别是，我们的分析表明，单个中子俘获元素的丰度变化不能由单一示踪剂（如[Ba/Fe]）来解释。这些发现阐明了中子俘获元素在化学标记中的效用，并突显了低分辨率光谱在此类研究中的潜力。
英文摘要
The scatter in elemental abundances among stars of similar age and metallicity reflects chemical inhomogeneity in their birth environments, making abundance scatter a key observable for chemical-tagging studies of Galactic formation and evolution. Using a large sample of subgiant stars with precise ages and elemental abundances derived from LAMOST low-resolution spectra, we investigate the intrinsic chemical abundance scatter of the low-$α$ thin disk near the solar neighborhood ($7 < R < 10$ kpc). We model the abundance ratio [X/Fe], for each of the 19 elements of concern, as a function of age, [Fe/H], and [Mg/Fe], and deduce the intrinsic dispersions with a forward modelling technique. Our results confirm previous findings that the intrinsic scatters are small, typically $\lesssim0.05$~dex, for light elements (C, Al), $α$-elements (O, Mg, Si, Ca, Ti), and iron-peak elements (Mn, Ni). A dedicated analysis of M67 yields similarly small scatter values for these elements, implying limited discriminatory power from light-element abundances alone. In contrast, neutron-capture elements exhibit substantially larger scatters, typically $\gtrsim$0.1 dex, which are significantly larger than those of M67 member stars ($\sim$0.07~dex). In particular, our analysis suggests that the abundance variations of individual neutron-capture elements cannot be explained by a single tracer such as [Ba/Fe]. These findings clarify the utility of neutron-capture elements for chemical tagging and highlight the potential of low-resolution spectroscopy in such studies.
Comments19 pages, 12 figures, accepted by MNRAS
