Astronomers from Harvard University have proposed the Sun may have been part of a binary system – where two stars orbit one another – in the solar system’s formative years. According to the researchers, if the Sun was part of a binary system, it could explain the Oort Cloud and ultimately how life came to be.
The Oort Cloud is a circumstellar cloud on the edge of our solar system which contains billions of icy objects.
The new theory from Harvard states that if there was a binary star system, it would have been better equipped at pulling distant objects in with its gravitational pull.
This could explain the formation of the Oort Cloud, with astronomers claiming the binary star system would have been able to pull in passing objects.
In turn, this could have then led to the formation of life on Earth.
With objects in the Oort Cloud containing ice and potentially molecules for the building blocks of life, an object from there could have come travelling through the solar system.
If said object then hit Earth, it could have delivered the basis of ice and water.
Amir Siraj, a Harvard undergraduate student involved in the research, said in a statement: “Previous models have had difficulty producing the expected ratio between scattered disk objects and outer Oort cloud objects.
“The binary capture model offers significant improvement and refinement, which is seemingly obvious in retrospect: most Sun-like stars are born with binary companions.
Co-author Avi Loeb said: “Binary systems are far more efficient at capturing objects than are single stars.
“If the Oort cloud formed as observed, it would imply that the Sun did in fact have a companion of similar mass that was lost before the Sun left its birth cluster.”
Mr Siraj added: “Objects in the outer Oort Cloud may have played important roles in Earth’s history, such as possibly delivering water to Earth and causing the extinction of the dinosaurs.”
However, the implications do not end there.
The team believe the binary system could have also helped to drag in the mysterious Planet 9 – a hypothetical object orbiting our solar system way out, past Neptune.
There are a number of odd features in our solar system that would be explained by Planet Nine.
One is that the Kuiper Belt – a circumstellar disc full of icy asteroids, comets and dwarf planets which encompasses the solar system – orbits in the opposite direction to the planets within it.
Another is that if the planet is there, then it could explain why the solar system is slightly off balance.
Next year, the Vera C Rubin Observatory (VRO) is set to begin operations and will help to look for “trans-Neptunian objects”.
The Harvard astronomers will be using the telescope to search for Planet 9 – which could be anything from a huge planet to a tiny black hole – which would add more weight to the binary star system theory.
Mr Siraj said: “If the VRO verifies the existence of Planet Nine, and a captured origin, and also finds a population of similarly captured dwarf planets, then the binary model will be favored over the lone stellar history that has been long-assumed.”
Dr Loeb: “It is unclear where they came from, and our new model predicts that there should be more objects with a similar orbital orientation to Planet Nine.”
However, the binary star, if it existed, is long gone and “could now be anywhere in the Milky Way” Mr Siraj concluded.
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