Kinematics and chemistry of the hot core in G20.08-0.14N

TL;DR

This study uses submillimeter observations to analyze the molecular composition, kinematics, and physical conditions of the hot core in G20.08-0.14N, revealing accretion flows, a collimated outflow, and chemical diversity.

Contribution

First detailed mapping of molecular distributions and kinematics in G20.08-0.14N's hot core, identifying accretion flows and outflow directions with chemical analysis.

Findings

Detection of 41 molecular transitions, including dominant SO2 lines.

Identification of two accretion flows and a collimated outflow in the region.

Confirmation that the hot core is heated by protostar radiation, not shocks.

Abstract

We present Submillimeter Array observations of the massive star-forming region G20.08-0.14N at 335 and 345 GHz. With the SMA data, 41 molecular transitions were detected related to 11 molecular species and their isotopologues, including SO2, SO, C34S, NS, C17O, SiO, CH3OH, HC3N, H13CO+, HCOOCH3 and NH2CHO. In G20.08-0.14N, 10 transition lines of the detected 41 transition lines belong to SO2, which dominates the appearance of the submillimeter-wave spectrum. To obtain the spatial kinematic distribution of molecules in G20.08-0.14N, we chose the strongest and unblended lines for the channel maps. The channel maps of C34S an SiO, together with their position-velocity diagrams, present that there are two accretion flows in G20.08-0.14N. Additionally, SiO emission shows a collimated outflow at the NE-SW direction. The direction of the outflow is for the first time revealed. The rotational temperature and the column density of CH3OH are 105 K and 3.1*10^{17} cm^{-2}, respectively. Our results confirm that a hot core is associated with G20.08-0.14N. The hot core is heated by a protostar radiation at it center, not by the external excitation from shocks. The images of the spatial distribution of different species have shown that the different molecules are located at the different positions of the hot core. Through comparing the spatial distributions and abundances of the molecules, we discuss possible chemical processes for producing the complex sulfur-bearing, nitrogen-bearing and oxygen-bearing molecules in G20.08-0.14N.