Unveiling the Kinematic Substructure of the Pleiades with Network Analysis

Abstract I apply network analysis to Gaia DR3 astrometry of the Pleiades to investigate the cluster’s internal kinematic structure. Using a Mahalanobis distance graph in proper-motion space, I identify the largest connected component of 1556 stars at a threshold of τ = 4.0. Louvain community detection then partitions this network into eight subgroups of sizes 741, 629, 75, 55, 39, 6, 6, and 5. The five highest-betweenness stars are highlighted; they play disproportionate structural roles in connectivity between distinct kinematic subgroups, rather than implying any specific dynamical mechanism. This graph-based approach provides a compact way to characterize substructure in nearby open clusters using Gaia astrometry.