Protostellar discs formed from turbulent cores

TL;DR

This study uses SPH simulations to explore how turbulent prestellar cores collapse and form protostellar discs, revealing that turbulence influences structure formation and disc stability.

Contribution

It demonstrates that turbulence-driven filament formation dominates core evolution, with most protostars developing discs, but only a few discs fragment due to gravitational instabilities.

Findings

82% of protostars have accretion discs

16% of discs are prone to fragmentation

Filamentary structures are key in core evolution

Abstract

We investigate the collapse and fragmentation of low-mass, trans-sonically turbulent prestellar cores, using SPH simulations. The initial conditions are slightly supercritical Bonnor-Ebert spheres, all with the same density profile, the same mass (M_O=6.1 Msun) and the same radius (R_O=17,000 AU), but having different initial turbulent velocity fields. Four hundred turbulent velocity fields have been generated, all scaled so that the mean Mach number is M=1. Then a subset of these, having a range of net angular momenta, j, has been evolved. The evolution of these turbulent cores is not strongly correlated with j. Instead it is moderated by the formation of filamentary structures due to converging turbulent flows. A high fraction (~ 82%) of the protostars forming from turbulent cores are attended by protostellar accretion discs, but only a very small fraction (~16%) of these discs is sufficiently cool and extended to develop non-linear gravitational instabilities and fragment.