Accreting Compact Object Binaries with the SKA

Accreting binary systems provide a time-resolved view of the accretion and ejection processes that are seen in all classes of compact objects, from stellar-mass to supermassive. They allow us to study the launching of relativistic jets on human timescales, probing how the jets are coupled to the underlying accretion flow, and providing unique insights that can be extended to supermassive black holes via the well-established mass scale invariance. Comparative studies of jets from different classes of compact objects allow us to determine the impact of mass, spin, magnetic fields, and stellar surfaces on the launching of jets. The jets from black hole X-ray binaries provide probes of the Galactic black hole population, and an important source of feedback to the surrounding interstellar medium. While existing radio facilities (including the SKA precursors) have made great progress in this field in recent years, the SKA will enhance such studies via its high point source and surface brightness sensitivity, high angular resolution, and broad frequency coverage. This will enable the extension of our existing black hole studies to the fainter accreting neutron star and white dwarf population, the detection of previously-undiscovered systems in a low-luminosity quiescent state, and the extension of our studies to nearby galaxies, revealing rare, high-accretion rate systems that probe a key phase of black hole growth.