The Effect of Shock Wave Duration on Star Formation and the Initial Condition of Massive Cluster Formation

TL;DR

This study uses 3D MHD simulations to explore how shock wave duration influences filament formation and the initial conditions for massive star cluster formation, revealing that longer shocks promote dense filament and cluster formation.

Contribution

It demonstrates the impact of shock duration on filament evolution and massive star cluster formation using detailed 3D MHD simulations with variable shock durations.

Findings

Longer shock durations lead to star formation via massive filaments.

Peak column density exceeds 10^23 cm^-2 when shock duration surpasses two free-fall times.

Massive clusters with about ten OB stars form in long-duration shock models.

Abstract

Stars are born in dense molecular filaments irrespective of their mass. Compression of the ISM by shocks cause filament formation in molecular clouds. Observations show that a massive star cluster formation occurs where the peak of gas column density in a cloud exceeds 10^23 cm^-2. In this study, we investigate the effect of the shock-compressed layer duration on filament/star formation and how the initial conditions of massive star formation are realized by performing three-dimensional (3D) isothermal magnetohydrodynamics (MHD) simulations with {gas inflow duration from the boundaries (i.e., shock wave duration)} as a controlling parameter. Filaments formed behind the shock expand after the duration time for short shock duration models, whereas long duration models lead to star formation by forming massive supercritical filaments. Moreover, when the shock duration is longer than two postshock free-fall times, the peak column density of the compressed layer exceeds 10^23 cm^-2, and {the gravitational collapse of the layer causes that} the number of OB stars expected to be formed in the shock-compressed layer reaches the order of ten (i.e., massive cluster formation).