Final answer:
Matter transfer through tidal forces in a binary star system occurs when one star loses matter to its companion, often forming an accretion disc and emitting X-ray radiation, affecting the stars' evolution and potentially leading to novas or supernovas.
Step-by-step explanation:
The process in which tidal forces cause matter to spill from one star to a companion star in a close binary system is known as the process of matter transfer through tidal forces. In such systems, if one star expands or has a strong stellar wind while in close proximity to its companion, material can flow from it to the other star. This process is facilitated by the mutual gravitational pull when the two objects are part of a binary star system, especially when they are in close orbit. The transferred material often forms an accretion disc around the recipient, such as a white dwarf, neutron star, or black hole, which can emit powerful X-ray radiation as it becomes super-heated. This scenario significantly influences the evolution of the stars involved, potentially leading to dramatic astrophysical events like novas or supernovas depending on the details of the mass transfer.