Optical and Near-Infrared Shocks in the L988 Cloud Complex

TL;DR

This study identifies new optical and near-infrared shocks in the L988 cloud, revealing multiple protostellar outflows, their sources, and large-scale structures, enhancing understanding of star formation processes in this region.

Contribution

The paper reports the discovery of new Herbig-Haro and MHO shocks, connecting them into outflow systems and identifying their protostellar sources, with detailed morphological analysis.

Findings

20 new Herbig-Haro objects identified

6 new MHO shocks discovered, including cross detections

Two outflows exceed 1 parsec in length and shape the cloud structure

Abstract

We have searched the Lynds 988 dark cloud complex for optical (\ha{} and \sii{}) and near-IR (\mh{} 2.12 $\mu$m) shocks from protostellar outflows. We find 20 new Herbig-Haro objects and 6 new \mh{} 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 5 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 LkHa 324SE.