Supernovae in Orion: The Missing Link in the Star-forming History of the Region
Marina Kounkel
Abstract
Abstract The Orion Complex is a notable star-forming region fragmented into several different populations with substantial differences in their phase space. I propose a model that attempts to explain the how the Complex has evolved into this current configuration. In the model presented here, the large-scale expansion can be attributable to a supernova that exploded 6 Myr ago. The remnants of this explosion can be seen as Barnard’s loop, as the center of the expansion is consistent with the geometrical center of the H ii bubble. This is similar to the H ii bubble and the ballistic expansion that is associated with λ Ori, a region that was also the site of an ancient supernova. Assuming that the Orion Complex originally formed as one long filament spanning from the bottom of Orion A to ψ 2 Ori (or potentially as far as λ Ori), Barnard’s loop supernova could have split the cloud, which led to the formation of Orion C & D. Furthermore, the shockwave that propagated into the filament could have swept along the gas through several parsecs, which led to the formation of the singularly most massive cluster in the solar neighborhood, the Orion Nebula Cluster. I also discuss other related nearby events, such as the formation of the Monogem ring and various runaways that have been ejected from the Orion Complex.