On the effects of solenoidal and compressive turbulence in pre-stellar cores

Abstract

We present the results of an ensemble of SPH simulations that followthe evolution of pre-stellar cores for 0.2 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, δsol, that is solenoidal, as opposed to compressive; specifically, we consider δsol =1, 2/3, 1/3, 1/9 and 0. For each value of δsol, we follow 10 different realizations of the turbulent velocity field, in order also to have ameasure of the stochastic variance blurring any systematic trends. With low δsol(<1/3), filament fragmentation dominates and delivers relatively high-mass stars. Conversely, with high values of δsol(>1/3) disc fragmentation dominates and delivers relatively low-mass stars. There are no discernible systematic trends in the multiplicity statistics obtained with different δsol.