The angular momentum of condensations within elephant trunks

TL;DR

This study uses 3D simulations to analyze how star-forming clumps within elephant trunks acquire angular momentum, revealing a preferential orientation perpendicular to the incident ionising radiation, which influences jet directions.

Contribution

The paper introduces detailed 3D simulation results showing the angular momentum orientation of collapsing clumps in photoevaporating clouds, a novel insight into star formation in such environments.

Findings

Clumps tend to have angular momentum perpendicular to the radiation source.

Jet axes from forming stars are likely oriented perpendicular to the ionising radiation.

Simulations reveal the angular momentum distribution during cloud photoevaporation.

Abstract

The radiation from newly born stars photoevaporates their parental neutral cloud, leading to the formation of dense clumps that will eventually form stars. We present 3D simulations of the interaction of a neutral cloud with an external ionising radiation field, and compute the angular momenta of these collapsing clumps. The angular momenta of these collapsing clumps show that they have preferential orient mostly perpendicular to the direction of the incident ionising photon field. Therefore, the axes of the jet systems that will be eventually ejected (from the star + accretion disk systems that will form) will be oriented approximately perpendicular to the direction to the photoionising source.