发表机构
Shanghai Astronomical Observatory, Chinese Academy of Sciences; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences（中国科学院上海天文台; 中国科学院大学天文与空间科学学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过模拟数据评估CSST与Gaia联合天体测量在暗弱星等下探测双星的能力，发现联合观测能显著提高轨道拟合成功率，并提出基于分类器筛选和规则后续观测的实用策略。
AI 中文摘要
背景。中国空间站巡天望远镜（CSST）将在其10年任务期间提供深度、大视场历元天体测量。天体测量双星轨道约束了恒星和致密天体成分的质量。轨道恢复依赖于天体测量精度和时间覆盖。结合CSST和Gaia数据可延长基线并提高双星探测能力。目标。我们评估CSST、Gaia及其联合天体测量在暗弱星等（$g>17.8$）下对双星候选体选择和12参数（12p）轨道拟合的性能。我们还测试了不同CSST观测节奏如何影响满足我们标准的12p拟合的产出。方法。我们构建了一个模拟星表，模拟了CSST和Gaia的历元天体测量，并拟合五参数（5p）单星模型以导出天体测量诊断量、自行异常特征和观测采样特征。一个四阶段直方图梯度提升分类器使用这些特征来选择候选体进行12p轨道拟合和评估。结果。在独立测试集上，分类器在符合条件的真实双星中达到了0.802的精确率和0.181的召回率。在特定场景的拟合样本中，联合天体测量将基准比例从仅Gaia的6.76%提高到10.46%；对于$P_{\rm true}>15{\rm yr}$的拟合双星，该比例从2.37%提高到6.78%。当前的CSST观测计划产生的基准拟合很少，而理想化的规则观测节奏主要增加了$g\lesssim21$星等范围内的产出。结论。在模拟中，CSST和Gaia联合历元天体测量相比仅Gaia方案，能获得更高比例的满足所述标准的未分辨双星拟合。一个实用策略是从5p诊断量和天体测量异常中选择候选体，获取更规则的CSST后续观测，然后拟合12p轨道模型并应用选择标准。
英文摘要
Context. The China Space-station Survey Telescope (CSST) will provide deep, wide-field epoch astrometry during its 10-year mission. Astrometric binary orbits constrain the masses of stellar and compact-object components. Orbital recovery depends on astrometric precision and temporal coverage. Combining CSST and Gaia data extends the baseline and improves binary detection. Aims. We evaluate CSST, Gaia, and joint astrometry for binary-candidate selection and 12-parameter (12p) orbit fitting at faint magnitudes ($g>17.8$). We also test how regular CSST cadences affect the yield of 12p fits satisfying our criteria. Methods. We constructed a mock catalog, simulated CSST and Gaia epoch astrometry, and fitted five-parameter (5p) single-star models to derive astrometric diagnostics, proper-motion anomaly features, and observational-sampling features. A four-stage histogram-based gradient-boosting classifier used these features to select candidates for 12p orbit fitting and assessment. Results. On the independent test set, the classifier reaches a precision of 0.802 and a recall of 0.181 among eligible true binaries. In the scenario-specific fitted samples, joint astrometry raises the fiducial fraction from 6.76% for Gaia alone to 10.46%; for fitted binaries with $P_{\rm true}>15{\rm yr}$, it rises from 2.37% to 6.78%. The current CSST schedule yields few fiducial fits, while idealized regular cadences increase the yield mainly at $g\lesssim21$. Conclusions. In the simulation, joint CSST and Gaia epoch astrometry yields higher fractions of fitted unresolved binaries satisfying the stated criteria than Gaia-only solution. A practical strategy is to select candidates from 5p diagnostics and astrometric anomalies, obtain more regular CSST follow-up observations, and then fit 12p orbital models and apply the selection criteria.
Comments18 pages, 4 tables, 10 figures, submitted to A&A
