AI 中文总结
研究盖亚DR3数据中共生星分类可靠性，构建随机森林分类器量化污染，有效分离多数共生双星与单颗演化恒星，确认三颗新共生星，指出分类纯度低，银河系共生星种群差异待解，盖亚提供搜索基础。
AI 中文摘要
我们研究了盖亚DR3一般变异性分类中共生星类别的可靠性，并在归入此类别的天体中寻找新的真正共生系统。样本包含649个源，包括246颗已知共生星、61个文献候选体和339个盖亚变异性管道提出的新候选体。基于盖亚色-星等图、近红外测光和Hα伪等效宽度的诊断表明，大部分新候选体可能是污染物，主要是脉动红巨星。为了量化污染，我们构建了一个随机森林分类器，用盖亚测光、变异性参数、XP光谱的Hα测量值和红外颜色在已确认的共生星以及米拉变星和半规则变星上进行训练。分类器达到了约0.94的平衡准确率，有效分离了大多数共生双星和单颗演化恒星，339个新提出的天体中仅留下8个强候选体。后续光谱学通过高激发发射线的存在确认了三颗新共生星，还有几个天体仍可能是共生体。我们的结果表明，盖亚DR3变异性分类能有效找回已知共生星，但由于与脉动红巨星重叠，纯度较低。新确认系统数量少意味着预测和观测到的银河系共生星种群之间的差异仍未解决，尽管盖亚为未来结合变异性、光谱指标和多波长数据的搜索提供了有力基础。
英文摘要
We investigate the reliability of the symbiotic star class in the general variability classification of Gaia DR3 and search for new genuine symbiotic systems among the objects assigned to this category. The sample contains 649 sources, including 246 previously known symbiotic stars, 61 literature candidates, and 339 new candidates proposed by the Gaia variability pipeline. Diagnostics based on the Gaia colour-magnitude diagram, near-infrared photometry, and the pseudo-equivalent width of H$α$ indicate that a large fraction of the new candidates are likely contaminants, predominantly pulsating red giants. To quantify the contamination, we constructed a Random Forest classifier trained on confirmed symbiotic stars and on Mira and semi-regular variables, using Gaia photometry, variability parameters, H$α$ measurements from XP spectra, and infrared colours. The classifier reaches a balanced accuracy of $\approx$0.94 and efficiently separates most symbiotic binaries from single evolved stars, leaving only eight strong candidates among the 339 newly proposed objects. Follow-up spectroscopy confirms three new symbiotic stars through the presence of high-excitation emission lines, while several additional objects remain possible symbiotics. Our results show that the Gaia DR3 variability classification efficiently recovers known symbiotic stars but has low purity due to overlap with pulsating red giants. The small number of newly confirmed systems implies that the discrepancy between predicted and observed Galactic symbiotic populations remains unresolved, although Gaia provides a powerful basis for future searches combining variability, spectroscopic indicators, and multi-wavelength data.
Comments14 pages, 11 figures, 1 table + appendices; accepted in MNRAS
