The Role of Discs in the Collapse and Fragmentation of Prestellar Cores

TL;DR

This paper uses SPH simulations to show how episodic protostellar feedback and solenoidal turbulence influence disc fragmentation, affecting star formation and mass distribution in prestellar cores.

Contribution

It demonstrates the conditions under which disc fragmentation occurs, highlighting the importance of episodic feedback and turbulence modes in star formation models.

Findings

Episodic accretion enables disc fragmentation by allowing gravitational instabilities.

Solenoidal turbulence modes are crucial for angular momentum and disc formation.

Fragmentation leads to realistic stellar mass distributions under specific conditions.

Abstract

Disc fragmentation provides an important mechanism for producing low mass stars in prestellar cores. Here, we describe Smoothed Particle Hydrodynamics simulations which show how populations of prestellar cores evolve into stars. We find the observed masses and multiplicities of stars can be recovered under certain conditions. First, protostellar feedback from a star must be episodic. The continuous accretion of disc material on to a central protostar results in local temperatures which are too high for disc fragmentation. If, however, the accretion occurs in intense outbursts, separated by a downtime of $\sim10^4\,\mathrm{years}$, gravitational instabilities can develop and the disc can fragment. Second, a significant amount of the cores' internal kinetic energy should be in solenoidal turbulent modes. Cores with less than a third of their kinetic energy in solenoidal modes have insufficient angular momentum to form fragmenting discs. In the absence of discs, cores can fragment but results in a top heavy distribution of masses with very few low mass objects.