Binary stars are systems where two stars orbit around a common center of mass. They are quite common in the universe, with estimates suggesting that about half of all stars are part of a binary system. These stars can be classified into different types based on their separation and brightness, including visual binaries, spectroscopic binaries, and eclipsing binaries. Studying binary stars is crucial for understanding stellar evolution and the dynamics of star systems. They provide valuable insights into the masses and sizes of stars, which are difficult to determine for single stars. Observations of binary stars have led to significant discoveries in astrophysics and cosmology.