A 3D View of Orion. I. Barnard's Loop

Barnard's Loop is a famous arc of H$\alpha$ emission located in the Orion star-forming region. Here, we provide evidence possible formation mechanism for and compare our results with recent work suggesting major feedback event occurred region around 6 Myr ago. We present 3D model large-scale region, indicating coherent, radial, expansion OBP-Near/Brice\~{n}o-1 (OBP-B1) cluster middle large dust cavity. The gas also appears to be expanding from central point, originally proposed X. OBP-B1 serve as another center, evaluate whether X or more likely cause expansion. find that neither served single but rather combination both propelled Recent maps are used characterize topology entire which shows Loop's correspondence cavity OPB-B1 cluster. molecular clouds A, B, $\lambda$ reside on shell this Simple estimates gravitational effects stars indicate asymmetric induced anisotropy kinematics OBP-B1. conclude has affected structure may have played role Loop.