ALMA Observations of the IRDC Clump G34.43+00.24 MM3: Hot Core and Molecular Outflows

TL;DR

This study uses ALMA and Keck observations to analyze a star-forming clump, revealing a hot core, a highly collimated outflow, and evidence of past star formation activity, highlighting early low-mass star formation in IRDC G34.43+00.24.

Contribution

First detailed ALMA and Keck multi-line observations of G34.43+00.24 MM3 revealing hot core, outflow, and star formation activity.

Findings

Detected a young, highly collimated outflow with a dynamical timescale <740 years.

Identified a hot core of about 800 x 300 AU with low mass but high accretion or multiple star presence.

Observed extended emission indicating past star formation activity.

Abstract

We have observed a cluster forming clump (MM3) associated with the infrared dark cloud G34.43+00.24 in the 1.3 mm continuum and the CH3OH, CS, 13CS, SiO, CH3CH2CN, and HCOOCH3 lines with the Atacama Large Millimeter/submillimeter Array and in K-band with the Keck telescope. We have found a young outflow toward the center of this clump in the SiO, CS, and CH3OH lines. This outflow is likely driven by a protostar embedded in a hot core, which is traced by the CH3CH2CN, HCOOCH3, 13CS, and high excitation CH3OH lines. The size of the hot core is about 800 x 300 AU in spite of its low mass (<1.1 M_sun), suggesting a high accretion rate or the presence of multiple star system harboring a few hot corinos. The outflow is highly collimated, and the dynamical timescale is estimated to be less than 740 yr. In addition, we have also detected extended emission of SiO, CS, and CH3OH, which is not associated with the hot core and the outflow. This emission may be related to past star formation activity in the clump. Although G34.43+00.24 MM3 is surrounded by a dark feature in infrared, it has already experienced active formation of low-mass stars in an early stage of clump evolution.