A molecular shell with recent star formation: Gas structure and stellar feedback in the RCW,122 region

Massive stars have a profound impact on their environments, shaping the interstellar medium through intense radiation and stellar winds. The expanding shells they produce can potentially trigger star formation. We aim to characterise a molecular shell located in the RCW,122 complex and investigate its origin, structure, and role in triggering star formation in the region. We analysed line data from the CO(3--2) and HCO+(4--3) transitions obtained with the ASTE telescope, complemented with infrared images from MSX, , and . The molecular shell's morphology and kinematics were characterised and the physical properties of dense condensations were derived. Additionally, we identified candidate massive stars and young stellar objects (cYSOs) using near- and mid-infrared photometric criteria and examined their spatial distribution relative to the shell. Herschel Spitzer -1 . The shell contains ten dense condensations, most of them associated with compact sources tracing cold, dense material. Several massive star candidates are projected inside the cavity and their wind energy budget is sufficient to account for the shell’s formation. Along the rim, we find seven regions, five extended green objects (EGOs), masers, and a population of cYSOs. A comparison with the analytical collect-and-collapse model indicates the process might not follow the classical scenario, but instead a more localised and rapid triggering mechanism operating in a complex, clumpy environment. This picture is consistent with recent observations of other Galactic bubbles. The results support a feedback-driven origin for the molecular shell and suggest recent star formation in a complex, clumpy molecular environment