Bow shocks in molecular clouds: H2 line strengths

Abstract

It is demonstrated that molecular-hydrogen emission-line ratios can be utilized to distinguish between models for shocks in molecular clouds. Planar and curved shocks of both C- and J-type are compared. Line strengths are determined from a model for bow-shaped C-shocks under high-density molecular cloud conditions. The line ratios are independent of the bow speed once it exceeds the breakdown value (typically 30-50 km/s). This is because the H 2 emitting section is simply shifted towards the bow tail at higher speeds.