The possibility of our solar system being a binary system with two suns, one large and one small, has been explored and theorized. While it is an intriguing idea, current scientific understanding and observations suggest that our solar system is not a binary system.
The primary reason for this is that the Sun, which is the central star of our solar system, does not have a stellar companion in close orbit. Extensive observations, including measurements of the Sun's gravitational influence on other celestial bodies, have not revealed the presence of a companion star within a significant distance.
However, it's worth noting that binary star systems are quite common in the universe. It is estimated that approximately half of all stars in the Milky Way galaxy exist in binary or multiple star systems. These systems consist of two or more stars that orbit around a common center of mass.
While our solar system does not currently exhibit characteristics of a binary system, it is possible that there could be distant, faint stellar companions that have not been detected yet due to their great distance and faintness. Future advancements in observational techniques and technology may provide further insights into the possibility of undiscovered companions in our solar system.