Accretion and the Properties of Protobinary Systems

Abstract

We discuss the evolution of the properties of a protobinary system which forms via fragmentation within a collapsing molecular cloud core and grows to its final mass by accreting from the gaseous envelope. We predict how the mass ratio distributions and the masses of the circumstellar and circumbinary discs depend on the binary's separation, the primary's mass, and the properties of the pre-collapse molecular cloud core. We also discuss how the properties of binaries may depend on whether they were formed in isolated molecular cloud cores or in stellar clusters.