High Velocity Outflow in CO J=7-6 from the Orion Hot Core

TL;DR

This study presents high-resolution CO J=7-6 observations of a high-velocity outflow in Orion's Hot Core, revealing a rapid, massive outflow driven by a forming massive star, with implications for star formation processes.

Contribution

First high-resolution mapping of CO J=7-6 emission in Orion Hot Core, revealing a high-velocity outflow with a very short dynamical timescale.

Findings

Detected outflow terminal velocity of 70-85 km/s.

Estimated outflow mass loss rate of ~10^{-3} Msun/yr.

Dynamical timescale of approximately 900 years.

Abstract

Using the Caltech Submillimeter Observatory 10.4-meter telescope, we performed sensitive mapping observations of 12CO J=7-6 emission at 807 GHz towards Orion IRc2. The image has an angular resolution of 10", which is the highest angular resolution data toward the Orion Hot Core published for this transition. In addition, thanks to the on-the-fly mapping technique, the fidelity of the new image is rather high, particularly in comparison to previous images. We have succeeded in mapping the northwest-southeast high-velocity molecular outflow, whose terminal velocity is shifted by ~70-85 km/s with respect to the systemic velocity of the cloud. This yields an extremely short dynamical time scale of ~900 years. The estimated outflow mass loss rate shows an extraordinarily high value, on the order of 10^{-3} Msun/yr. Assuming that the outflow is driven by Orion IRc2, our result agrees with the picture so far obtained for a 20 Msun (proto)star in the process of formation.