Binary stars are very useful for determining the mass of the stars and thus any objects orbiting around them.
the orbits of binary stars
No
their orbits in binary systems
Kepler's third law is used in the study of binary stars to determine the masses of the stars based on their orbital periods. By observing the motion of the stars in their orbits, scientists can apply Kepler's third law to calculate the masses of the stars and understand their gravitational interactions.
Two stars orbiting each other are "binary stars" ...a group of stars near each other, may be formally or informally known as a "cluster".
Binary stars can be any color that stars can be. There's no need for the two stars in a binary to be the same color.
do you mean a purple star?? then the answer would be no!! If you mean is it possible that there is a red and blue Binary star system, where one orbits the other. Then the answer would have to be yes as there are no rules governing how a binary system is formed
Roughly half of all stars in the galaxy are estimated to be part of binary or multiple star systems. This means approximately 50% of stars are binary stars.
Binary stars
Stellar masses can be determined by observing binary star-systems. The calculations of the orbits of the binary stars allow the masses of their component stars to be directly determined, which in turn allows other stellar parameters, such as radius and density, to be indirectly estimated.
Stars orbit the center of their galaxy due to gravity. In our solar system, planets orbit around the Sun in elliptical orbits. Additionally, binary star systems have stars that orbit around each other.
By definition, a binary star system has two stars in it.