Machine learning-enabled membership determination of open cluster AH03_J0748-26.9 using Gaia DR3 astrometry

As populations of stars born concurrently, open clusters serve as fundamental laboratories for validating models of star formation, stellar evolution, and the dynamical processes of the Galactic disk. This paper provides a comprehensive astrometric and photometric analysis of the open cluster AH03_J0748-26.9, leveraging data from the Gaia DR3 catalog. We employ the Hierarchical Density-Based Spatial Clustering of Applications with Noise (HDBSCAN) algorithm to analyze astrometric data from Gaia Data Release 3 (DR3). Our analysis characterizes the identified clusters through several fundamental parameters, specifically the census of probable members, spatial radii, age, distance, the initial mass function (IMF), and total cluster mass.We determined a concentration parameter of [Formula: see text] for AH03_J0748-26.9. The estimated number of members for AH03_J0748-26.9 is 128 stars. A distance modulus of [Formula: see text] mag and an age of 114.815 Myr ([Formula: see text]) were derived using PARSEC isochrone fitting. Given a relaxation time of 32.125 Myr and an age of 114.815 Myr ([Formula: see text]), the cluster AH03_J0748-26.9 is found to be dynamically relaxed. We analyzed the mass function (MF) for AH03_J0748-26.9 using a Monte Carlo method coupled with synthetic cluster modeling. We characterized the MF over the range 0.102-[Formula: see text] by fitting a two-segment broken power law, deriving slopes of [Formula: see text] (for [Formula: see text]) and [Formula: see text] (for [Formula: see text]) with a characteristic break mass of [Formula: see text]. The steep slope in the higher mass regime suggests a deviation from the canonical Salpeter IMF, which is consistent with the effects of dynamical evolution and mass segregation. By integrating this best-fit MF and adopting a binary fraction of [Formula: see text]-typical for concentrated open clusters-we estimate a total cluster mass of [Formula: see text]. A sensitivity analysis indicates that varying the binary fraction between 0.5 and 0.9 alters the total mass estimate by approximately [Formula: see text], supporting the robustness of the mass scale. A sample of 128 member stars yielded a mean radial velocity of [Formula: see text]. These kinematic data, combined with proper motions, served as input for the galpy package to determine the cluster's Galactic orbit.