论文标题
揭示开放恒星簇的分层结构：珀尔修斯双重群集
Unveiling the Hierarchical Structure of Open Star Clusters: the Perseus Double Cluster
论文作者
论文摘要
我们介绍了一种新的运动学方法，以研究开放型星团的结构。我们采用了一种分层聚类算法，该算法使用天体坐标和恒星在群集视野中的正确运动，以估算恒星的成对结合能的代理，并将它们排列在二元树中。根据$σ$ -Plateau方法，通过将树修剪为两个阈值来确定群集子结构及其成员。在100个模拟目录上测试算法表明，平均而言，确定的簇的成员资格为$（91.5 \ pm 3.5）$ \％$ \％完成，无关星星的分数为$（10.4 \ pm 2.0）$ \％。我们将算法应用于盖亚（Gaia）数据释放2的珀尔修斯双重群集视野中的恒星。这种方法标识了单个结构sub1，该结构分为两个子结构SUB1-1和SUB1-2。这些子结构与每$ $ h $和$χ$相吻合：SUB1-1和SUB1-2成员的适当动作和颜色刻度图的分布完全与文献中每报道的$ H $和$χ$的分布完全一致。这些结果表明，我们的分层聚类算法可以是公开星团复杂运动信息的强大工具。
We introduce a new kinematic method to investigate the structure of open star clusters. We adopt a hierarchical clustering algorithm that uses the celestial coordinates and the proper motions of the stars in the field of view of the cluster to estimate a proxy of the pairwise binding energy of the stars and arrange them in a binary tree. The cluster substructures and their members are identified by trimming the tree at two thresholds, according to the $σ$-plateau method. Testing the algorithm on 100 mock catalogs shows that, on average, the membership of the identified clusters is $(91.5\pm 3.5)$\% complete and the fraction of unrelated stars is $(10.4\pm 2.0)$\%. We apply the algorithm to the stars in the field of view of the Perseus double cluster from the Data Release 2 of Gaia. This approach identifies a single structure, Sub1, that separates into two substructures, Sub1-1 and Sub1-2. These substructures coincide with $h$ Per and $χ$ Per: the distributions of the proper motions and the color-magnitude diagrams of the members of Sub1-1 and Sub1-2 are fully consistent with those of $h$ Per and $χ$ Per reported in the literature. These results suggest that our hierarchical clustering algorithm can be a powerful tool to unveil the complex kinematic information of star clusters.
