On the effects of solenoidal and compressive turbulence in prestellar cores

TL;DR

This study uses SPH simulations to investigate how the ratio of solenoidal to compressive turbulence influences the fragmentation and star formation outcomes in prestellar cores, revealing different fragmentation modes and star masses.

Contribution

It systematically explores the impact of varying solenoidal versus compressive turbulent energy fractions on core fragmentation and star formation, providing new insights into turbulence effects.

Findings

Filament fragmentation dominates at low solenoidal fractions, leading to higher mass stars.

Disc fragmentation dominates at high solenoidal fractions, leading to lower mass stars.

No clear trend in multiplicity statistics with varying turbulence composition.

Abstract

We present the results of an ensemble of SPH simulations that follow the evolution of prestellar cores for $0.2\,{\rm Myr}$. All the cores have the same mass, and start with the same radius, density profile, thermal and turbulent energy. Our purpose is to explore the consequences of varying the fraction of turbulent energy, $\delta_\mathrm{sol}$, that is solenoidal, as opposed to compressive; specifically we consider $\delta_\mathrm{sol}=1,\,2/3,\,1/3,\,1/9\;{\rm and}\;0$. For each value of $\delta_\mathrm{sol}$, we follow ten different realisations of the turbulent velocity field, in order also to have a measure of the stochastic variance blurring any systematic trends. With low $\delta_\mathrm{sol}(<\!1/3)$ filament fragmentation dominates and delivers relatively high mass stars. Conversely, with high values of $\delta_\mathrm{sol}(>\!1/3)$ disc fragmentation dominates and delivers relatively low mass stars. There are no discernible systematic trends in the multiplicity statistics obtained with different $\delta_\mathrm{sol}$.