Secondary outflow driven by the protostar Ser-emb 15 in Serpens

TL;DR

This study reports the discovery of a secondary outflow from the Class I protostar Ser-emb 15, revealing complex outflow structures and potential binary or single star formation scenarios in the Serpens Molecular Cloud.

Contribution

It provides the first detailed observation of a secondary outflow associated with Ser-emb 15, using high-resolution ALMA data to analyze outflow morphology and potential driving sources.

Findings

Detection of two pairs of molecular outflows with ALMA.

Identification of two compact sources, A and B, near Ser-emb 15.

Discussion of possible binary or single star system driving the outflows.

Abstract

We present the detection of a secondary outflow associated with a Class I source, Ser-emb 15, in the Serpens Molecular Cloud. We reveal two pairs of molecular outflows consisting of three lobes, namely primary and secondary outflows, using ALMA 12CO and SiO line observations at a resolution of 318 au. The secondary outflow is elongated approximately perpendicular to the axis of the primary outflow in the plane of the sky. We also identify two compact structures, Sources A and B, within an extended structure associated with Ser-emb 15 in the 1.3 mm continuum emission at a resolution of 40 au. The projected sizes of Sources A and B are 137 au and 60 au, respectively. Assuming a dust temperature of 20 K, we estimate the dust mass to be 0.0024 Msun for Source A and 0.00033 Msun for Source B. C18O line data imply the existence of rotational motion around the extended structure, however, cannot resolve rotational motion in Source A and/or B, due to insufficient angular and frequency resolutions. Therefore, we cannot conclude whether Ser-emb 15 is a single or binary system. Thus, either Source A or B could drive the secondary outflow. We discuss two scenarios to explain the driving mechanism of the primary and secondary outflows: the Ser-emb 15 system is (1) a binary system composed of Source A and B or (2) a single star system composed of only Source A. In either case, the system could be a suitable target for investigating the disk and/or binary formation processes in complicated environments. Detecting these outflows should contribute to understanding complex star-forming environments, which may be common in the star-formation processes.