AI 中文总结
研究银河系盘中[Y/Mg]-年龄关系的空间变化，通过分析高分辨率恒星光谱，严格考虑NLTE效应确定镁和钇丰度及星震年龄等，发现该关系有系统空间变化，反映恒星形成和化学富集历史差异。
AI 中文摘要
基于之前的研究，该研究证明了在元素丰度测定中考虑偏离局部热动平衡（LTE）以及使用星震年龄的重要性，我们使用大量更大的恒星样本研究了银河系盘中经验性[Y/Mg]-年龄关系的空间变化。我们分析了高分辨率恒星光谱，通过对多个光谱特征进行光谱合成来确定镁和钇的丰度，并严格考虑非局部热动平衡（NLTE）效应。我们推导了表现出太阳型振荡的恒星的星震年龄，并对其余恒星使用基于等时线的交叉检验方法。我们确定了528颗银河系场星的大气参数、镁和钇的丰度，以及307颗恒星的星震年龄和221颗恒星的等时线年龄。我们还识别了两个新的三线和九个双线光谱系统。将本样本与之前研究的样本相结合，共得到736颗恒星，用于研究银河系盘中的[Y/Mg]-年龄关系。该关系显示出系统的空间变化，可能反映了恒星形成和化学富集历史的差异。一般来说，在研究的年龄范围内，[Y/Mg]倾向于随金属丰度增加。然而，在超太阳金属丰度下，这种趋势可能会减弱，[Y/Mg]-年龄关系比太阳金属丰度恒星的关系更平坦，太阳金属丰度恒星在年轻时[Y/Mg]值较低，在老年时较高。
英文摘要
Building on our previous study, which demonstrated the importance of accounting for departures from local thermodynamic equilibrium (LTE) in elemental-abundance determinations and of using asteroseismic ages, we investigate spatial variations in the empirical [Y/Mg]-age relation across the Galactic disc using a substantially larger stellar sample. We analysed high-resolution stellar spectra and determined Mg and Y abundances through spectral synthesis of multiple spectral features, rigorously accounting for non-LTE (NLTE) effects. We derived asteroseismic ages for stars exhibiting solar-type oscillations and used cross-checked isochrone-based methods for the remaining stars. We determined atmospheric parameters and Mg and Y abundances for 528 Galactic field stars, together with asteroseismic ages for 307 stars and isochronal ages for 221 stars. We also identified two new triple-lined and nine double-lined spectroscopic systems. Combining the present sample with that of our previous study yielded a total of 736 stars, which we used to examine the [Y/Mg]-age relation across the Galactic disc. The relation shows systematic spatial variations that likely reflect differences in star-formation and chemical-enrichment histories. In general, [Y/Mg] tends to increase with metallicity over the investigated age range. At supersolar metallicity, however, this trend may weaken, and the [Y/Mg]-age relations become flatter than those of solar-metallicity stars, which show lower [Y/Mg] values at young ages and higher values at old ages.
Comments10 pages, 11 figures
