AI 中文总结
该研究利用LAMOST和APOGEE的红团簇星，探究银河系薄盘和厚盘径向金属丰度梯度随垂直高度和恒星年龄的变化。通过特定公式描述其变化规律，揭示了薄盘和厚盘不同的形成机制，如薄盘由有序生长和演化形成，厚盘在早期快速形成。
AI 中文摘要
利用来自郭守敬望远镜（LAMOST）和阿帕奇角星系演化实验（APOGEE）的200388颗红团簇星，我们研究了银河系盘的径向金属丰度梯度随垂直高度和恒星年龄的变化。薄盘在银道面附近呈现出明显的负径向金属丰度梯度，随着|Z|增加逐渐变平，遵循特定公式。薄盘在径向金属丰度梯度上也表现出明显的年龄依赖性。厚盘显示出微弱的正径向金属丰度梯度，在垂直高度和恒星年龄方面统计上保持不变，也遵循相应公式。这些结果表明薄盘保留了由相对有序的由内向外生长和长期的长期演化过程形成的径向金属丰度梯度。厚盘表现出空间和时间上均匀的径向金属丰度梯度，支持了它在盘动态热且有效混合的早期阶段快速形成的图景，可能是在富含气体的系统的混沌合并和/或湍流星际介质中形成的。
英文摘要
Using 200,388 red clump stars from LAMOST and APOGEE, we investigate the radial metallicity gradients of the Galactic disk as a function of vertical height and stellar age. The thin disk displays a pronounced negative radial metallicity gradient near the Galactic mid-plane that progressively flattens with increasing $|Z|$, following $Δ\mathrm{[Fe/H]}/ΔR$ = $-$0.0784 $+$ 0.0776 (1 $-$ exp ($-$ $|Z|$/1.42)). The thin disk also exhibits a clear age dependence in radial metallicity gradients, evolving smoothly from a strong gradient regime for young stars to a weak gradient regime for old stars, following $Δ\mathrm{[Fe/H]}/ΔR$ = $-$0.0438 $+$ 0.0233 tanh (($τ$ $-$ 11.29)/4.21). The thick disk shows weakly positive radial metallicity gradients that remain statistically invariant with respect to both vertical height and stellar age, following respectively, $Δ\mathrm{[Fe/H]}/ΔR$ = 0.0038 $+$ 0.0009 $|Z|$ and $Δ\mathrm{[Fe/H]}/ΔR$ = 0.0146 $-$ 0.0007 $τ$. These results indicate that the thin disk retains radial metallicity gradients shaped by relatively ordered inside-out growth and long-term secular evolution processes. The thick disk exhibits spatially and temporally homogeneous radial metallicity gradients, which are consistent with a formation environment characterized by mergers of gas-rich systems and/or the turbulent ISM.
Comments7 pages, 7 figures, accepted for publication in ApJL
