论文标题
GAIA-ESO调查：银河系薄磁盘中的氧气丰度
The Gaia-ESO Survey: Oxygen abundance in the Galactic thin and thick disks
论文作者
论文摘要
我们分析了两个主要银河种群的恒星样品的氧气丰度：薄和厚的磁盘。目的是研究银河磁盘成员之间的差异，并有助于对银河系中氧化学富集起源的理解。该分析基于[o \，{\ sc i}] = 6300.30 \，Å〜氧气线中的HR光谱（$ r \ sim $ 52,500）从GES调查中获得。通过将观察到的光谱与一个理论数据集进行比较，并在LTE中与光谱合成和ATLAS12代码进行了比较，我们得出了我们以前已经测量过的碳丰度的516 FGK矮人的氧气丰度。基于运动学，化学和动力学考虑因素，我们确定了20个薄和365个厚的磁盘成员。我们研究了两个子样本的潜在趋势，这些趋势是根据它们的化学（[O/H]，[O/Fe]，[O/Mg]和[C/O]与[Fe/H]和[Fe/H]和[Mg/H]），年龄和位置在银河系中的潜在趋势。主要结果是：（a）[o/h]和[o/fe]比[fe/h]显示出薄磁盘恒星和厚磁盘恒星之间的系统差异，与薄磁盘构件相对于薄磁盘成员的O含量增强，并且随着金属富含金属富含金属富含金属富含金属的金属性的增加，[o/fe]的单调降低； （b）[O/mg]与年龄在两个人群中的平滑相关性，这表明这种丰度比可以很好地代表银河系以内的恒星年龄； （c）具有[Fe/H] $ \ simeq0 $的薄磁盘成员显示A [C/O]比太阳值小，这表明可能会从下层中心半径的下向太阳向外迁移。
We analyze the oxygen abundances of a stellar sample representative of the two major Galactic populations: the thin and thick disks. The aim is to investigate the differences between members of the Galactic disks and to contribute to the understanding on the origin of oxygen chemical enrichment in the Galaxy. The analysis is based on the [O\,{\sc i}]=6300.30\,Å~ oxygen line in HR spectra ($R\sim$52,500) obtained from the GES Survey. By comparing the observed spectra with a theoretical dataset, computed in LTE with the SPECTRUM synthesis and ATLAS12 codes, we derive the oxygen abundances of 516 FGK dwarfs for which we have previously measured carbon abundances. Based on kinematic, chemical and dynamical considerations we identify 20 thin and 365 thick disk members. We study potential trends of both subsamples in terms of their chemistry ([O/H], [O/Fe], [O/Mg], and [C/O] versus [Fe/H] and [Mg/H]), age, and position in the Galaxy. Main results are: (a) [O/H] and [O/Fe] ratios versus [Fe/H] show systematic differences between thin and thick disk stars with enhanced O abundance of thick disk stars with respect to thin disk members and a monotonic decrement of [O/Fe] with increasing metallicity, even at metal-rich regime; (b) a smooth correlation of [O/Mg] with age in both populations, suggesting that this abundance ratio can be a good proxy of stellar ages within the Milky Way; (c) thin disk members with [Fe/H]$\simeq0$ display a [C/O] ratio smaller than the solar value, suggesting a possibly outward migration of the Sun from lower Galactocentric radii.
