Dents in the Veil: Protostellar feedback in Orion

TL;DR

This study investigates how protostellar jets and outflows from B-type stars influence the Orion Veil shell, revealing their significant role in shaping the interstellar medium and contributing to turbulence and morphology of HII regions.

Contribution

It provides new evidence that protostellar feedback from B-type stars impacts the Orion Veil, expanding understanding of stellar feedback beyond massive O-type stars.

Findings

Protostellar jets create dents in the Veil shell.

B-type star outflows influence shell dynamics.

Protostellar feedback affects HII region morphology.

Abstract

Interest in stellar feedback has recently increased because new studies suggest that radiative and mechanical feedback from young massive stars regulate the physical and chemical composition of the interstellar medium (ISM) significantly. Recent SOFIA [CII] 158 micron observations of the Orion Veil revealed that the expanding bubble is powered by stellar winds and influenced by previously active molecular outflows of ionizing massive stars. We aim to investigate the mechanical feedback on the whole Veil shell by searching for jets/outflows interacting with the Veil shell and determining the origin/driving mechanisms of these collisions. In the light of these findings, as well as the momenta of the dents and their dynamical timescales, we propose that the dents are created by the interaction of collimated jets/outflows from protostars with luminosities ranging from 10$^3$ to 10$^4$ $L_\odot$ indicating B-type stars in the Orion star-forming cloud with the surrounding Veil shell. However, it is challenging to pinpoint the driving stars as they may have moved from the original ejection points of the jets/outflows. We conclude that the dynamics of the expanding Veil shell is influenced not just by the O-type stars in the Trapezium cluster, but also by less massive stars, especially B-type, in the Orion Nebula. Mechanical feedback from protostars with a range of masses appears to play an important role in determining the morphology of [HII] regions and injecting turbulence into the medium.