2025ApJ...986...20C

This study provides an in-depth analysis of the ancient open galactic cluster NGC 6253, characterized by the presence of both blue and yellow straggler stars. Utilizing a hybrid approach that integrates DBSCAN and Gaussian mixture models with GAIA Data Release 3, we effectively identified the cluster members, discovering 11 blue and 7 yellow stragglers. The structure of the cluster considerably exceeds its tidal radius, which implies that there is an evident tidal tail structure. A calculated relaxation time of 32.469 Myr, which is considerably shorter than its 3.5 Gyr age, indicates that NGC 6253 has attained dynamic relaxation. The mass segregation timescale observed for most stars in our sample is brief compared to the cluster's age, offering strong evidence of mass segregation. Orbital integration using the MWPotential2014 model and analysis of binary members further corroborate our results. The birth radius of 6.78 kpc suggests formation within the solar circle. Our research into the present mass function reveals a top-heavy distribution common to both single and binary star populations. Additionally, our analysis shows that among binary systems, more massive binaries are more centrally located compared to their less massive counterparts, underscoring the significant role of binary stars in shaping the cluster's overall mass distribution.