One, Two, Three ... An Explosive Outflow in IRAS 12326$-$6245 revealed by ALMA

TL;DR

This paper reports the discovery of an explosive molecular outflow in IRAS 12326-6245 using high-resolution ALMA observations, revealing multiple streamers and a dusty shell, with implications for the rate of such events in the galaxy.

Contribution

It presents the first detailed observation of an explosive outflow in IRAS 12326-6245, including the identification of a dusty shell and estimation of explosion parameters.

Findings

Over 10 molecular streamers with expansion motions identified.

Estimated explosion age of approximately 700 years.

Event rate of one explosive outflow every 90 years in the Galaxy.

Abstract

In the last years there has been a substantial increase in the number of the reported massive and luminous star-forming regions with related explosive outflows thanks to the superb sensitivity and angular resolution provided by the new radio, infrared, and optical facilities. Here, we report one more explosive outflow related with the massive and bright star-forming region IRAS 12326$-$6245 using Band 6 sensitive and high angular resolution ($\sim$0.2$"$) Atacama Large Millimeter/Submillimeter Array (ALMA) observations. We find over 10 molecular and collimated well-defined streamers, with Hubble-Lemaitre like expansion motions, and pointing right to the center of a dusty and molecular shell (reported for the first time here) localized in the northern part of the UCHII region known as G301.1A. The estimated kinematic age, and energy for the explosion are $\sim$700 yrs, and 10$^{48}$ erg, respectively. Taking into account the recently reported explosive outflows together with IRAS 12326$-$6245, we estimate an event rate of once every 90 yr in our Galaxy, similar to the formation rate of massive stars.