Fast molecular jet from L1157-mm

TL;DR

This study identifies a high-velocity molecular jet from L1157-mm using SiO emissions, linking it to shock-induced chemical activity in the outflow's hot-spots, and providing insights into jet dynamics in star-forming regions.

Contribution

First detection of an unresolved high-velocity molecular jet from L1157-mm via SiO lines, connecting jet activity to chemical hot-spots in the outflow.

Findings

High-velocity SiO components are about 45 km/s from ambient cloud.

Jet is unresolved in SiO(5-4) with size <11".

Jet likely excites chemically active spots in the outflow.

Abstract

L1157-mm powers a molecular outflow that is well-known for its shock-induced chemical activity in several hot-spots. We have studied the molecular emission toward L1157-mm searching for a jet component responsible for these spots. We used the IRAM 30m telescope to observe the vicinity of L1157-mm in several lines of SiO. The SiO(5-4) and SiO(6-5) spectra toward L1157-mm present blue and red detached components about 45 km/s away from the ambient cloud. These extremely high-velocity (EHV) components are similar to those found in the L1448 and IRAS 04166+2706 outflows, and probably arise from a molecular jet driven by L1157-mm. Observations of off-center positions indicate that the jet is unresolved in SiO(5-4) (<11"). The EHV jet seen in SiO probably excites L1157-B1 and the other chemically active spots of the L1157 outflow.