We present the star formation activity around the emission nebula Sh2-112. At a distance of ~2.1kpc, this HII complex, itself 3pc in radius, is illuminated by the massive star (O8 V) BD+45 3216. The associated molecular cloud extends in angular scales of 2.0x0.83{deg}, corresponding to linear sizes of 73pc by 30pc, along the Galactic longitude. The high-resolution (30") extinction map reveals a chain of dust clumps aligned with the filament-like structure with an average extinction of A_V_~2.78mag, varying up to a maximum of ~17mag. Our analysis led to identification of a rich population (~500) of young (average age of ~1Myr) stars, plus a numerous number (~350) of H{alpha} emitters, spatially correlated with the filamentary clouds. Located near the edge of the cloud, the luminous star BD+45 3216 has created an arc-like pattern as the ionizing radiation encounters the dense gas, forming a blister-shaped morphology. We found three distinct young stellar groups, all coincident with relatively dense parts of the cloud complex, signifying ongoing star formation. Moreover, the cloud filament (excitation temperature ~10K) traced by the CO isotopologues and extending nearly ~80pc is devoid of ionized gas except at the dense cores (excitation temperature ~28-32K) wherein significant ionized emission excited by OB stars (dynamical age ~0.18-1.0Myr) pertains. The radial velocity is dynamic (median ~-3.65km/s) along the main filament, increasing from Galactic east to west, indicating mass flow to form the massive stars/clusters at the central hubs.

Cone search capability for table J/ApJ/939/46/table1 (Photometric catalog of the YSOs toward S112)

Cone search capability for table J/ApJ/939/46/table2 (Photometric catalog of the H{alpha} emitters toward S112)