Star Cluster Formation in Clouds with Externally Driven Turbulence

TL;DR

This study compares two turbulence driving methods in molecular cloud simulations, revealing that external driving produces more realistic star cluster formations similar to observations.

Contribution

It introduces a comparative analysis of turbulence driving methods, highlighting the impact of external versus full-volume driving on star formation and cloud morphology.

Findings

Externally driven turbulence results in larger, more centralized star clusters.

Fully driven turbulence produces dispersed, smaller star-forming regions.

Externally driven simulations align better with observed star cluster properties.

Abstract

Star clusters are known to be formed in turbulent molecular clouds. How turbulence is driven in molecular clouds and what effect this has on star formation is still unclear. We compare a simulation setup with turbulent driving everywhere in a periodic box with a setup where turbulence is only driven around the outside of the box. We analyse the resulting gas distribution, kinematics, and the population of stars that are formed from the cloud. Both setups successfully produce a turbulent velocity field with a power law structure function, the externally driven cloud has a more central, monolithic, clump, while the fully driven cloud has many smaller, more dispersed, clumps. The star formation follows the cloud morphology producing large clusters, with high star forming efficiency in the externally driven simulations and sparse individual star formation with much lower star formation efficiency in the fully driven case. We conclude that the externally driven method, which resembles a Global Hierarchical Collapse (GHC) scenario, produces star clusters that more closely match with observations.