A team of researchers from Harvard University in the USA, in a recent article, proposes a theory that is at least intriguing: the Sun once had a sister, a similar star that made up a binary system with it. However, the stars were “separated at birth”, not without leaving marks on the composition of the solar system.
The “clue” about the lost sister of the Sun would be the Oort cloud, a cluster of asteroids, comets and planetoids like Sedna or Quaoar, in the outer reaches of the solar system. It is divided into two areas, the internal, which is shaped like a disk, and the external, which spheres. But previous models for the formation of the solar system could not explain this configuration.
“Previous models had difficulty producing the expected proportion of objects in the inner and outer clouds,” says Amir Siraj, a graduate student at Harvard, who was involved in the research. “The binary capture model is much more refined, something that seems obvious in retrospect: most stars similar to the Sun are born with binary companions.”
According to Avi Loeb, co-author of the article, “binary systems are much more efficient at capturing objects than individual stars. If the Ooort cloud formed as observed, this would imply that the Sun did, in fact, have a mass companion similar that was lost before he left the cluster where he was born “.
The theory may impact studies on the origin of life on our planet. “Objects in the Oort cloud may have played important roles in Earth’s history, such as possibly bringing water to the planet (in the form of ice in comets) or even causing the extinction of the dinosaurs,” says Siraj.
And what was the fate of the “sister” of the Sun? The team suggests that the pairing was undone by the gravitational influence of other stars, born along with the Sun in the same star cluster. “The Sun’s lost companion can be anywhere on Via Lctea,” he says.
Astronomy Stars Sun Solar system Science & Space space exploration