论文标题
改善GAIA DR3 GSP Spec目录中非常金属贫困星的金属估计值
Improving metallicity estimates for very metal-poor stars in the Gaia DR3 GSP-Spec catalog
论文作者
论文摘要
VMP恒星的GAIA DR3 GSP-SPEC参数（包括金属性）因其光谱中缺乏信息而遭受参数退化。此外，推荐的质量将大多数VMP星星过滤掉了，因为其中一些与热星或凉爽的K和M型巨头相混淆。我们旨在通过在分析中考虑光度信息来为通过GSP规格模块分析的VMP恒星提供更精确的金属性估计。我们通过计算出已发布的GSP-Spec恒星参数集的CA三重速度等效宽度来重新分析GSP-Spec目录中的FGK型星。我们将这些回收的等效宽度与直接从公共Gaia RVS光谱测量的值进行比较，并研究恢复值的精度和恢复值可靠的参数范围。然后，我们将回收的等效宽度转换为采用光度温度和表面重力的金属度。恢复的等效宽度与直接测量值的值一致，而通过GSP规格质量切割的恒星散射为0.05 DEX。在低金属末端（[Fe/H] $ <-1.5 $）下，我们的金属性估计值典型的不确定性为0.18 DEX，这约为同一金属性的GSP Spec金属不确定性的一半。与低金属性的原始GSP规格金属性相比，我们的金属度与高分辨率文献值也更好。当包括``热''恒星且包括``酷k和m型巨人''的子集时表现出越来越多的GSP规格金属率，但我们现在可以将它们识别为FGK型恒星，并提供比较中较小散射的金属性。得益于这些最初错误分类的恒星的回收，我们将可靠金属性的VMP恒星数量增加了2-3美元。
The Gaia DR3 GSP-Spec parameters, including metallicity, for VMP stars suffer from parameter degeneracy due to a lack of information in their spectra. Furthermore, the recommended quality cuts filter out the majority of the VMP stars because some of them are confused with hot stars or cool K and M-type giants. We aim to provide more precise metallicity estimates for VMP stars analysed by the GSP-Spec module by taking photometric information into account in the analysis. We reanalyzed FGK type stars in the GSP-Spec catalog by computing the Ca triplet equivalent widths from the published set of GSP-Spec stellar parameters. We compare these recovered equivalent widths with the values directly measured from public Gaia RVS spectra and investigate the precision of the recovered values and the parameter range in which the recovered values are reliable. We then convert the recovered equivalent widths to metallicities adopting photometric temperatures and surface gravities. The recovered equivalent widths agree with the directly measured values with a scatter of 0.05 dex for the stars that pass the GSP-Spec quality cuts. At the low metallicity end ([Fe/H]$<-1.5$), our metallicity estimates have a typical uncertainty of 0.18 dex, which is about half of the quoted GSP-Spec metallicity uncertainty at the same metallicity. Our metallicities also show better agreement with the high-resolution literature values than the original GSP-Spec metallicities at low metallicity. While the GSP-Spec metallicities show increasing scatter when misidentified ``hot'' stars and the subsets of the ``cool K and M-type giants'' are included, we can now identify them as FGK-type stars and provide metallicities that show a small scatter in the comparisons. Thanks to the recovery of these originally misclassified stars, we increase the number of VMP stars with reliable metallicity by a factor of $2-3$.
