Alfonso, JeisonJeisonAlfonsoGarcia-Varela, AlejandroAlejandroGarcia-VarelaVieira, KatherineKatherineVieira2026-07-072026-07-072026PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC, 138(6), 064201 (2026). https://doi.org/10.1088/1538-3873/ae72040004-62801538-3873https://hdl.handle.net/20.500.12740/24746Stellar mass governs stellar evolution, and the distribution of stellar masses plays a central role in the dynamical evolution of stellar clusters. Using high-precision astrometry and photometry from Gaia DR3, we investigate mass segregation and the present-day mass function (PDMF) in fifteen nearby open clusters. Single and binary stars are identified from the color-magnitude diagram, and stellar masses for single stars are derived from a cubic spline relation with G-band magnitude, while binary component masses are estimated via a simulation-based inference method. Based on these mass estimates, mass segregation is quantified using the minimum spanning tree technique, and the PDMF is characterized through power-law fitting. We detect significant mass segregation in all clusters. Systems lacking very massive stars exhibit weaker segregation affecting a larger fraction of the population, whereas clusters hosting a small number of very massive stars show strong central concentration of these objects. The PDMF follows a power law with a slope of (2.01 +/- 0.25), consistent with the canonical Kroupa initial mass function. The strength of mass segregation correlates with the mass of the most segregated stars. Strong segregation observed in very young clusters supports a primordial origin, while older clusters display signatures of dynamical mass segregation at lower masses and evidence of binary disruption. A low-mass break in the PDMF observed in most clusters, if not due to incompleteness, may reflect early gas expulsion in initially mass-segregated systems.info:eu-repo/semantics/openAccessINITIAL MASS FUNCTIONMESA ISOCHRONESSTAR-CLUSTERSSEGREGATIONASTROPYI.PLEIADESBINARIESPACKAGEPROJECTArticulohttps://doi.org/10.1088/1538-3873/ae7204