Optical and near-infrared shocks in the l988 cloud complex

摘要

We have searched the Lynds 988 dark cloud complex for optical (Hα and S II) and near-IR (H2 2.12 μm) shocks from protostellar outflows. We find 20 new Herbig-Haro objects and 6 new H2 shocks (MHO objects), 3 of which are cross detections. Using the morphology in the optical and near-IR, we connect several of these shocks into at least five distinct outflow systems and identify their source protostars from catalogs of infrared sources. Two outflows in the cloud, from IRAS 21014+5001 and IRAS 21007+4951, are in excess of 1 pc in length. The IRAS 21007+4951 outflow has carved a large cavity in the cloud through which background stars can be seen. Also, we have found an optical shock which is the counterflow to the previously discovered "northwest outflow" from LkHα 324SE.