In theory, there is no maximum number of stars a planet can orbit. However, the stability of a planet's orbit depends on a variety of factors, including the gravitational interactions between the planet and the stars it orbits. The more stars a planet orbits, the more complex and dynamically challenging its orbital dynamics become.
In binary star systems, where two stars orbit each other, it is possible for planets to exist and stably orbit both stars. These are known as circumbinary planets. Examples of such systems include Kepler-16, Kepler-34, and Kepler-35. These planets have been discovered through observations made by the Kepler space telescope.
In recent years, astronomers have also discovered some exoplanets orbiting triple star systems, such as HD 188753 and Gliese 667. These systems have more complex dynamics compared to binary star systems, but stable planetary orbits can still be possible depending on the specific parameters of the system.
As the number of stars in a planetary system increases, the stability of planetary orbits becomes increasingly challenging to maintain. Factors such as the masses, distances, and orbital configurations of the stars play critical roles in determining the long-term stability of planetary systems.
In summary, while there is no theoretically defined maximum number of stars a planet can orbit, the complexity and stability of the planetary system increase as the number of stars involved grows.