Hydrodynamic Simulations of Proplyd Bow Shocks

Faint high{ionization arcs of emission are found to be associated with some of the proplyds in the Orion nebula. These arcs are typically oset by 0.5{4 arcsec from the proplyds, in the direction of the ionizing star ( 1 C Ori) and have commonly been interpreted as bowshocks, resulting from the collision between the transonic photoevaporating o w from the proplyd and the highly supersonic (1000 km s 1) stellar wind from 1 C Ori. We present two{dimensional hydrodynamic simulations of the wind{wind interaction (photoevaporating o w and supersonic wind). The results of our numerical simulation with the analytical solution for the position and the shape of the thin shell formed are compared by the interaction between two winds (spherical and plane-parallel). We compare the predicted intensity maps of our simulations with observations of the proplyd 167{317.