#stellar systems

a stellar system

Although our own Solar system only contains one star, many stellar systems include two stars (binaries), or an even greater number of stellar components. In this lecture, I discuss the variety of architectures of stellar systems, addressing questions such as what fraction of stellar systems are multiple, and how the stars in a multiple system orbit each other. Emphasis will be put on explaining Kepler's laws of celestial motion, which can be used as a basis to understand the orbits of everything from stars to planets to moons and man-made satellites. Finally, I examine how the study of binary systems has been, and remains, crucial to the determination of the fundamental properties of stars.