X-Ray Binaries & Accretion Physics: Observation, Measurement & Evidence

Systems can be fed by Roche-lobe overflow or by capture from a stellar wind. The inflow often forms an accretion disk with a hot inner region, corona, winds, and in some cases relativistic jets. Neutron-star systems may also show bursts or pulsations from a material surface and magnetic field.

X-ray spectra, rapid variability, Doppler-shifted companion-star lines, eclipses, and orbital mass functions reveal compact objects. Chandra and other X-ray observatories resolve binaries in the Milky Way and external galaxies.

Angular momentum forces transferred gas into orbit before it can fall inward. Magnetic or turbulent stresses move angular momentum outward, allowing matter to spiral inward and convert gravitational binding energy into heat and radiation.

Orbital spectroscopy measures the unseen companion mass function, while X-ray spectra, eclipses, quasi-periodic variability, bursts, and radio jets constrain the accretion system.