Here's why:

* Stars are massive objects: Stars are much larger and more massive than planets. They generate their own light and heat through nuclear fusion.

* Gravity and orbits: Gravity is what causes objects to orbit each other. The more massive an object, the stronger its gravitational pull. While planets orbit stars due to the star's gravity, stars are not massive enough to cause another star to orbit them.

* The Sun's influence: The Sun is the dominant gravitational force in our solar system. It holds all the planets, asteroids, comets, and other objects in orbit around it.

However, stars can be part of binary star systems or multiple star systems where two or more stars orbit each other due to their mutual gravitational pull.