STATISTICAL ANALYSIS OF THE SPATIAL STRUCTURE AND EVOLUTION OF STELLAR CLUSTERS USING GAIA MISSION DATA

Abstract

This study presents a comparative analysis of the spatial structure and physical-population evolution of the open clusters NGC 1981 and M45 (Pleiades) using astrometric and photometric data from the Gaia Data Release 3 (DR3). Variables including effective temperature, luminosity, parallax, proper motion, and color index (BP-RP) were extracted, comprising samples exceeding 5,000 stars per cluster. The statistical approach included descriptive analysis, Kolmogorov-Smirnov test for distribution assessment, Mann-Whitney non-parametric test for inter-cluster comparison, and Spearman correlation to evaluate monotonic relationships among physical parameters. The results revealed statistically significant differences (p < 0.05) in temperature, luminosity, and color index distributions between clusters, indicating distinct evolutionary stages. Correlation matrices showed variations in the strength of relationships among stellar parameters, suggesting differences in structural organization and internal dynamical conditions. Hertzsprung–Russell diagrams confirmed non-coincident population patterns, particularly in the relative concentration of hotter and more luminous stars. The convergence of descriptive, inferential, and structural evidence supports the robustness of the applied statistical framework. We conclude that Gaia DR3 is a powerful tool for comparative investigations of stellar evolution, enabling reliable discrimination of structural patterns in open clusters.