A team of Harvard astronomers have a wild new theory: the Sun used to have a companion star, making our solar system a binary one during its ancient history.
The astronomers say the theory could explain the formation of the Oort cloud, a theoretical cloud of dust and smaller objects in the distant regions of our solar system that many believe was created out of the left overs from the early solar system.
In a new preprint submitted last month to the preprint archive arXiv, the team suggests that the Sun used to have a long lost binary star companion. Such a system could explain how some objects were scattered to the far reaches of the solar system, sometimes even making it to neighboring systems and vice versa.
“Previous models have had difficulty producing the expected ratio between scattered disk objects and outer Oort cloud objects,” Amir Siraj, a Harvard undergraduate student involved in the research, said in a statement. “The binary capture model offers significant improvement and refinement, which is seemingly obvious in retrospect: most Sun-like stars are born with binary companions.”
A binary star system would be far more likely to capture the Oort cloud.
The theory could explain the existence of Planet Nine.