The Origin and Evolution of Multiple Star Systems
  Most stars are born in multiple stellar systems. Observational advances over
the last decade have enabled high-resolution, interferometric studies of
forming multiple systems, statistical surveys of multiplicity in star-forming
regions, and new insights into disk evolution and planetary architectures in
these systems. In this review, we compile the results of observational and
theoretical studies of stellar multiplicity. We summarize the population
statistics spanning system evolution from the protostellar phase through the
main-sequence phase and evaluate the influence of the local environment. We
describe current models for the origin of stellar multiplicity and review the
landscape of numerical simulations and assess their consistency with
observations. We review the properties of disks and discuss the impact of
multiplicity on planet formation and system architectures. Finally, we
summarize open questions and discuss the technical requirements for future
observational and theoretical progress.
