Abstract
Abstract We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm continuum and molecular-line observations of the star-forming region G40.282−0.219. The continuum resolves the source, previously considered a single massive young stellar object (MYSO), into three compact cores within a common natal clump. Using 13 bright molecular transitions, we investigate gas kinematics, chemistry, and evolutionary differences among the cores. MM1 is the dominant continuum source. MM2, the second-brightest core, drives a powerful outflow; its SiO jet shows velocity offsets of ±25 km s −1 from the systemic velocity. SiO jet and wider-angle H 2 CO and CH 3 OH emission trace the outflow, whose alignment with the H 2 knot MHO 2463 suggests a preceding ejection from MM2. MM3 is weakest in continuum but appears to be the principal hot core, harboring Class II 6.7 GHz CH 3 OH masers and the richest molecular inventory, including complex organic molecules (CH 3 OH and CH 3 CN) and shock/dense-gas tracers (OCS, HC 3 N, H 2 CO, and SO). We find clear spatial decoupling between continuum brightness and chemical, outflow, and maser activity. MM1 appears chemically poor, whereas weaker MM2 harbors outflow activity, and the least-bright MM3 contains an MYSO, the highest dust temperature, and the greatest chemical complexity. These hot cores may represent an evolutionary sequence from youngest MM1 to most evolved MM3 within one fragmenting clump. We conclude that accretion luminosity, localized heating, and evolutionary stage, rather than 1.3 mm continuum flux, likely govern observable chemical richness in clustered high-mass star-forming regions.