EPoS Contribution
EPoS Contribution
Prestellar cores and protostellar multiple systems

Oliver Lomax
Cardiff U, Cardiff, GB
Using an ensemble SPH simulations, we follow the evolution of prestellar cores as they collapse and fragment into protostars. The initial conditions for these simulations are constructed to match the observed properties of the cores in Ophiuchus. The protostars that form match the statistics of observed young protostars (IMF and multiplicity statistics, including triples, quadruples, quintuples and sextuples) but only if (i) radiative feedback from protostars is episodic, and (ii) the turbulent velocity field has a significant solenoidal component. A majority of protostars is attended by significant discs, but in multiple systems these discs are often poorly aligned with one another and/or the binary orbit, reflecting the stochastic nature of the accretion flows that feed material into the centre of a core. We also present synthetic spectra and images of multiple systems embedded in protostellar cores. These are calculated using a new Smoothed Particle Monte Carlo Radiative Transfer algorithm.
Caption: A sequence of column density maps of a core during disc fragmentation. The initial core has mass 1.3 Msol, radius 3000 au and velocity dispersion 0.3 km/s. The colour-bar gives shows the column density in units of g/cm2. The black dots show the positions of sink particles, i.e. protostars. Fig. (a) shows gravitational instabilities developing in a circumbinary disc. Fig. (b) shows seven protostars in an unstable configuration. In Fig. (c), the protostars are configured in a quadruple system (right) and a binary (left); a single protostar is being ejected (centre). Fig. (d) shows a stable sextuple system which lasts until the end of the simulation.
A.P. Whitworth, Cardiff U, GB
D.A. Hubber, LMUM, DE
Key publication

Suggested Session: Cores and Collapse