Most stars in our Universe live in Binary and multiple systems. Understanding these objects is critical for practically all fields of astrophysics. The presence of a companion significantly alters the evolution of a star and results in a plethora of unusual objects including type Ia supernovae, symbiotic stars, classical novae, or post-common-envelope systems. Observations of the binary stars enable us to directly determine masses, radii, and luminosities of stars. These are necessary inputs for all models of stellar structure and evolution. The presence of binary and multiple systems affects all galactic environments including stellar associations, open and globular clusters.

The field of binary systems significantly benefits from numerous all-sky surveys and satellite missions which are primarily focused on exoplanets or pulsating stars. The unprecedented precision of the satellite data revolutionized research of binary stars. Numerous fine effects are being routinely observed and must be taken into account in the modeling. The continuous satellite photometry led to the detection of long-period eclipsing binaries and multiply-eclipsing multiple systems. The study of binaries also benefits from a simultaneous analysis of different types of observations including radial velocities, line profiles, multi-color photometry, astrometry, or polarimetry. In spite of substantial progress in the field there are still many open questions. Those include the formation of close binaries and multiple systems, the common-envelope evolution, the magnetic dynamo, and activity in binary stars or stellar mergers.

The scientific meeting will be organized in the city of Litomyšl, Czech Republic, on the week of September 9 - 13, 2024. The city will be honouring Zdenek Kopal, one of the foremost investigators of binary stars who was born in this city in 1914. A similar, smaller-scale conferences in the same city took place in 2004 and 2014 (