Supersonic Expansion of the Bipolar H ii Region Sh2-106: A 3500 Year Old Explosion?

Abstract Multi-epoch narrowband Hubble Space Telescope images of the bipolar H ii region Sh2-106 reveal highly supersonic nebular proper motions that increase with projected distance from massive young stellar object S106 IR, reaching over ∼30 mas yr −1 (∼150 km s at D = 1.09 kpc) a separation ∼1.′4 (0.44 pc) IR. We propose IR experienced ∼10 47 erg explosion ∼3500 ago. The may be result major accretion burst or recent encounter another star, consequence interaction companion bloated photosphere as it grew through ∼15 M ⊙ high rate. Near-IR fingers 2 emission pointing away and an asymmetric photon-dominated surrounding ionized nebula. Radio continuum Br γ C-shaped bend in plasma, indicating either motion toward east, deflection plasma west by cloud. bends around ∼1′ diameter dark bay shielded direct illumination dense molecular clump. Herbig–Haro Molecular Hydrogen Objects tracing outflows powered stars protocluster such Class 0 source FIR are discussed.