Extremely high velocity gas from the massive YSOs in IRAS 17233-3606

TL;DR

This study investigates high-velocity molecular outflows from massive young stellar objects in IRAS 17233-3606, revealing highly collimated flows with velocities exceeding 120 km/s, indicative of very young, massive star formation processes.

Contribution

First detailed analysis of extremely high velocity outflows in a massive YSO, demonstrating multiple components and high collimation in IRAS 17233-3606.

Findings

Detected at least three outflow components with high velocities

Identified a highly collimated outflow with a collimation factor ~4

Estimated outflow ages between 100 and 1000 years

Abstract

Molecular outflows from high-mass young stellar objects provide an excellent way to study the star formation process, and investigate if they are scaled-up versions of their low-mass counterparts. We selected the nearby massive star forming region IRAS 17233-3606 in order to study the kinematics and physics along the molecular outflow(s) originating from this source. We observed IRAS 17233-3606 in CO, a typical tracer of gas associated with molecular outflow, with the Submillimeter Array in the (2-1) transition, and with the APEX telescope in the higher excitation (6-5) line. Additional infrared H2 observations were performed with the UKIRT telescope. The CO data were analysed using a LVG approach. Our data resolve the previously detected molecular outflow in at least three different components, one of them with a high collimation factor ~4, and characterised by emission at extremely high velocities (|v-v_{LSR}|>120 km s^{-1}). The estimate of the kinematical outflow parameters are typical of massive YSOs, and in agreement with the measured bolometric luminosity of the source. The kinematic ages of the flows are in the range 10^2-10^3 yr, and therefore point to young objects that still did not reach the main sequence.