A new theory published today in the Astrophysical Magazine Letters by scientists from Harvard University suggests that the sun once had a binary companion with the same mass. As confirmed, the presence of an early stellar companion increases the chance that the Oort cloud is formed as observed and that Planet Nine was captured instead of formed within the solar system.
Dr. Avi Loeb, Frank B. Baird Jr. Professor of science at Harvard, and Amir Siraj, a Harvard undergraduate student, have postulated that the existence of a long-lost stellar binary companion in the solar cluster of the sun – the collection of stars that formed along with the sun from the same dense cloud of molecular gas – could explain the formation of the Oort cloud as we observe it today.
Popular theory associates the formation of the Oort cloud with punctures left over from the formation of the solar system and its neighbors, where objects were scattered across the planet by large planets and some were exchanged between stars. But a binary model could be the missing piece in the puzzle, and according to Siraj should not come as a surprise to scientists. Earlier models 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 evident in the background: most solar-like stars are born with binary companion. “
If the Oort cloud were indeed captured with the help of an early stellar companion, the implications for our understanding of the formation of the solar system would be significant. “Binary systems are much more efficient at capturing objects than single stars,” Loeb said. “If the Oort cloud formed as observed, it would imply that the sun actually had a companion of the same mass that was lost before the sun left its birth cluster.”
More than just redefining the formation of our solar system, evidence from a captive Oort cloud could answer questions about the origin of life on Earth. “Objects in the outer Oort Cloud may have played important roles in the history of the Earth, such as possibly supplying water to Earth and causing the extinction of the dinosaurs,” Siraj said. “Beginning of their origin is important.”
The model also has implications for the Planet Nine hypothesis, which Loeb and Siraj believe is not only there. “The puzzle is not only about the Oort clouds, but also extreme trans-Neptunian objects, such as the potential Planet Nine,” Loeb said. “It is unclear where they came from, and our new model predicts that there should be more objects with a similar orbital orientation as Planet Nine.”
Both the Oort cloud and Planet Nine’s proposed location are so far from the sun that direct observation and observation are challenging for today’s researchers. But the Vera C. Rubin Observatory, which sees first light in early 2021, will confirm or deny the existence of Planet Nine and its origins. Siraj is optimistic, “If the VRO verifies the existence of Planet Nine, and finds an established origin, as well as a population of similarly established dwarf planets, then the binary model will be favored over the solitary stellar history that has long been adopted. “
If the sun had an early companion, which contributed to the formation of the outer solar system, its present absence begs the question: where did it go then? “Passing stars in the birth cluster would have removed the companion from her sun due to her gravity impact,” Loeb said. “Before the loss of the binary, however, the solar system would have captured all of its outer envelope of objects, namely the Oort cloud and the population of the Planet Nine.” Siraj added, “The long-lost companion of the sun could now be anywhere in the Milky Way.”
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The Case for an Early Solar Binary Companion, arXiv: 2007.10339 [astro-ph.EP] arxiv.org/abs/2007.10339
Supplied by Harvard-Smithsonian Center for Astrophysics
Citation: The sun may have started its life with a binary guide (2020, August 18) picked up August 18, 2020 from https://phys.org/news/2020-08-sun-life-binary-companion.html
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