Answer:
- binary stars
Explanation:
A binary star is a star system. It is composed of its stars that orbit the same center of mass, that is, orbit around each other.
If two stars orbit each other, but maintaining a great distance from each other, they evolve independently and are called a separate pair. If they are close enough for matter to transfer between them due to tidal forces, they are called close pair or contact.
Binary stars obey Kepler's Laws of Planetary Motion, which are three:
- 1st law (law of orbits): Each star moves along an elliptical orbit, with the center of mass of the system at one of the foci of this ellipse.
- 2nd law (law of areas): the line connecting one star to another scans equal areas at equal time intervals.
- 3rd law (harmonic law): The square of the orbital period of the stars is proportional to the cube of their average distance to each other.
