Laws of Physics & Astronomy for Binary Stars include Kepler's Three Laws of Planetary Motion , Newton's Three Laws of Motion, and Newton's Law of Gravity. When all of these laws are combined mathematically Kepler's Laws , which were determined emperically, can be derived from Newton's Laws. This match of theory to observation applied to binary star orbits gives astronomers powerful tools with which they can determine some physical characteriscis of stars.
Physical Properties of Stars Determined from Binary Stars include stellar masses, radii, and luminosity.