AI 中文总结
研究利用LAMOST DR10的光谱铁丰度为训练标签，从盖亚DR3数据估计恒星金属丰度。通过交叉匹配数据训练XGBoost模型，验证其在多数据集上表现良好，能准确测量银河系盘径向金属丰度梯度，目录和模型公开可用于银河系化学研究。
AI 中文摘要
盖亚DR3为数亿颗恒星提供了天体物理参数，但其GSP-Phot模块的金属丰度[M/H]存在系统偏差。我们利用LAMOST DR10的均匀光谱铁丰度[Fe/H]作为训练标签，从盖亚DR3数据中估计恒星金属丰度。将LAMOST DR10与盖亚DR3交叉匹配，仅使用盖亚派生的输入和代理，在120万颗AFGK恒星上训练了梯度提升决策树回归器（XGBoost）。在保留的LAMOST恒星、GALAH DR4、APOGEE DR17和46个疏散星团上进行验证，并应用该模型测量银河系盘的径向金属丰度梯度。在保留的测试集上，该模型实现了平均绝对误差0.052 dex和\(R^2 = 0.94\)，偏差可忽略不计，而GSP-Phot在相同恒星上的误差为0.242 dex。估计值在外部调查中转移良好，GALAH的平均绝对误差为0.066 dex，APOGEE为0.068 dex。对于疏散星团，我们估计的[Fe/H]与光谱值之间的中位数差异为0.041 dex，小于GSP-Phot（0.248 dex）和先前APOGEE训练的XGBoost模型（0.067 dex）。应用于银河系盘，我们的模型恢复了一个断裂的薄盘径向梯度，内斜率和外斜率分别为\(+0.119\)和\(-0.058\,\mathrm{dex\,kpc^{-1}}\)，断裂点在5.9 kpc附近，疏散星团梯度为\(-0.066\,\mathrm{dex\,kpc^{-1}}\)；两者均与先前的高分辨率光谱研究一致。对于\([\mathrm{Fe/H}]\gtrsim -2.5\)的AFGK恒星，我们的[Fe/H]估计精度为0.05 - 0.07 dex；低于此极限，预测应视为下限。目录和训练模型可在Zenodo上公开获取，适用于银河系的化学研究。
英文摘要
Gaia DR3 provides astrophysical parameters for hundreds of millions of stars, but the metallicities [M/H] from its GSP-Phot module suffer from systematic biases. We estimate stellar metallicities from Gaia DR3 data using the homogeneous spectroscopic iron abundances [Fe/H] of LAMOST DR10 as training labels. We cross-matched LAMOST DR10 with Gaia DR3 and trained a gradient-boosted decision-tree regressor (XGBoost) on 1.20 million AFGK stars using only Gaia-derived inputs and proxies. We validated the estimates on held-out LAMOST stars, GALAH DR4, APOGEE DR17, and 46 open clusters, and applied the model to measure the radial metallicity gradient of the Milky Way disk. On the held-out test set, the model achieves a mean absolute error of 0.052 dex and $R^2=0.94$ with negligible bias, compared with 0.242 dex for GSP-Phot on the same stars. The estimates transfer well to external surveys, with mean absolute errors of 0.066 dex for GALAH and 0.068 dex for APOGEE. For open clusters, the median difference between our estimated [Fe/H] and spectroscopic values is 0.041 dex, smaller than both GSP-Phot (0.248 dex) and a previous APOGEE-trained XGBoost model (0.067 dex). Applied to the Galactic disk, our model recovers a broken thin-disk radial gradient, with inner and outer slopes of $+0.119$ and $-0.058\,\mathrm{dex\,kpc^{-1}}$, respectively, and a break near 5.9 kpc, as well as an open-cluster gradient of $-0.066\,\mathrm{dex\,kpc^{-1}}$; both agree with previous high-resolution spectroscopic studies. Our [Fe/H] estimates are accurate to 0.05-0.07 dex for AFGK stars with $[\mathrm{Fe/H}]\gtrsim-2.5$; below this limit, the predictions should be treated as lower bounds. The catalogue and trained model are publicly available on Zenodo and are suitable for chemical studies of the Milky Way.
Comments12 pages, 16 figures
