Our Sun May Have Started Its Life with a Binary Companion

Sun Companion

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Artist’s conception of a prospective solar buddy, which theorists think was established in the Sun’s birth cluster and later on lost. If tested, the solar buddy theory would supply extra credence to theories that the Oort cloud formed as we see it today, which Planet Nine was recorded instead of formed in location. Credit: M. Weiss

A brand-new theory released just recently in The Astrophysical Journal Letters by researchers from Harvard University recommends that the Sun might when have had a binary buddy of comparable mass. If validated, the existence of an early excellent buddy increases the probability that the Oort cloud was formed as observed which Planet Nine was recorded instead of formed within the planetary system.

Dr. Avi Loeb, Frank B. Baird Jr. Professor of Science at Harvard, and Amir Siraj, a Harvard undergraduate trainee, have actually postulated that the presence of a long-lost excellent binary buddy in the Sun’s birth cluster—the collection of stars that formed together with the Sun from the exact same thick cloud of molecular gas—might describe the development of the Oort cloud as we observe it today.

Popular theory associates the development of the Oort cloud with particles left over from the development of the planetary system and its next-door neighbors, where things were spread by the worlds to country miles and some were exchanged among stars. But a binary design might be the missing out on piece in the puzzle, and according to Siraj, shouldn’t come as a surprise to researchers. “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.”

If the Oort cloud was undoubtedly recorded with the aid of an early excellent buddy, the ramifications for our understanding of the planetary system’s development would be considerable. “Binary systems are far more efficient at capturing objects than are single stars,” stated Loeb. “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.”

More than simply redefining the development of our planetary system, proof of a caught Oort cloud might respond to concerns about the origins of life on Earth. “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,” stated Siraj. “Understanding their origins is important.”

The design likewise has ramifications for the assumed Planet Nine, which Loeb and Siraj think isn’t alone out there. “The puzzle is not only regarding the Oort clouds, but also extreme trans-Neptunian objects, like the potential Planet Nine,” stated 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.”

Both the Oort cloud and the proposed area of Planet Nine are so remote from the Sun that direct observation and evaluation are challenging for today’s scientists. But the Vera C. Rubin Observatory, which sees very first light in early 2021, will verify or reject the presence of Planet Nine and its origins. Siraj is positive, “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.”

If the Sun did have an early buddy that added to the development of the external planetary system, its existing lack pleads the concern: where did it go? “Passing stars in the birth cluster would have removed the companion from the Sun through their gravitational influence,” stated Loeb. “Before the loss of the binary, however, the solar system already would have captured its outer envelope of objects, namely the Oort cloud and the Planet Nine population.” Siraj included, “The Sun’s long-lost buddy might now be throughout the Milky Way.”

Reference: “The Case for an Early Solar Binary Companion” by Amir Siraj and Abraham Loeb, 18 August 2020, The Astrophysical Journal Letters.
DOI: 10.3847/2041-8213/abac66