Using Molecular Gas Observations to Guide Initial Conditions for Star Cluster Simulations

TL;DR

This paper introduces a method to convert observed gas properties in star-forming regions into initial conditions for simulations of star cluster formation, demonstrated with the Orion Nebula Cluster, highlighting the influence of gas properties on cluster evolution.

Contribution

The authors develop a novel technique to derive initial conditions for star cluster simulations from observational gas data, including assessments of missing information impacts.

Findings

Gas cloud properties affect star formation rate and cluster assembly.

Results are insensitive to gas velocity assumptions in the plane of the sky.

Stars become more tightly clustered as new stars form in filaments.

Abstract

The earliest evolution of star clusters involves a phase of co-existence of both newly-formed stars, and the gas from which they are forming. Observations of the gas in such regions provide a wealth of data that can inform the simulations which are needed to follow the evolution of such objects forward in time. We present a method for transforming the observed gas properties into initial conditions for simulations that include gas, stars, and ongoing star formation. We demonstrate our technique using the Orion Nebula Cluster. Since the observations cannot provide all the necessary information for our simulations, we make choices for the missing data and assess the impact of those choices. We find that the results are insensitive to the adopted choices of the gas velocity in the plane of the sky. The properties of the surrounding gas cloud (e.g. overall density and size), however, have an effect on the star formation rate and pace of assembly of the resultant star cluster. We also analyze the stellar properties of the cluster and find that the stars become more tightly clustered and in a stronger radial distribution even as new stars form in the filament.