Recent Advances in Binary Star Formation Using SPH

Abstract

We review recent advances in the study of binary star formation that have been made using the smoothed particle hydrodynamics (SPH) technique. We discuss the importance of ensuring that the Jeans mass is always resolved during a self-gravitating SPH calculation. Even obeying this criterion, we show that it is now possible to perform calculations which follow the collapse of a molecular cloud core all the way to stellar densities. These calculations resolve 7 orders of magnitude in spatial extent and 17 orders of magnitude in density contrast. Finally, we discuss the progress that has been made in understanding the mass-ratio distributions of binary stellar systems by studying the evolution of protobinary systems as they accrete gas from their surrounding envelopes.