Feedback-driven Interaction of Expanding Molecular Clouds in the LDN 1204–Sh 2-145–Sh 2-140 Complex

We present a multiwavelength study of an extended molecular cloud hosting the LDN 1204, Sh 2-145, and Sh 2-140 regions to investigate the interplay between stellar feedback, cloud dynamics, and star formation. Infrared images reveal two semi-arc/shell-like structures (extent ∼14–18 pc) associated with known massive O-type stars. Herschel temperature and column density maps identify one hub-filament system (HFS) candidate toward both the LDN 1204A and LDN 1204B subregions, with peak column densities of ∼3.1 × 10 23 and ∼1.3 × 10 23 cm −2 , respectively. These subregions are located at the periphery of the Sh 2-145 H ii region. Molecular line data reveal a large arc-/shell-like cloud resolved into two kinematically distinct components spanning ∼−15 to −9.5 km s −1 and ∼−9 to −3 km s −1 . Each component exhibits an arc-/shell-like morphology, is centered on one of the massive stars, and displays an inverted-C-shaped position–velocity structure, indicating expansion driven by its associated H ii region. Both LDN subregions are located at the projected interface of the two expanding cloud components. Young stellar objects (YSOs), particularly Class I YSOs, are concentrated toward these subregions, while moment 2 maps reveal enhanced velocity dispersion, suggesting increased turbulent motions at the interface. Altogether, the presence of dense filaments, candidate HFSs, and active star formation in LDN 1204 subregions demonstrates that feedback-driven shell expansion and interaction compressed the gas at the interface, establishing the necessary conditions for filaments and ongoing star formation. These results highlight the important role of feedback-driven cloud interactions in regulating dense structure formation and star formation in molecular clouds.