Our Sun was likely born with a twin star: study
Our Sun probably had a twin when it appeared there 4.5 billion years ago, say scientists who have found that all stars in the universe were born with a partner.
Many stars have companions, including our nearest neighbor, Alpha Centauri, a triple system. Astronomers have long sought an explanation.
Astronomers have even sought out a companion to our Sun, a star named Nemesis, as they are supposed to have launched an asteroid in Earth orbit that hit our planet and exterminated the dinosaurs. It has never been found.
Researchers, including those at the University of California, Berkeley in the United States, conducted a radio study of a giant molecular cloud filled with newly formed stars in the Perseus constellation.
They also created a mathematical model that can explain Perseus’ observations as if all stars like the sun appear with a partner.
“We said, yes, that was probably a nemesis, a long time ago,” said co-author Steven Stahler, researchers at the University of Berkeley.
“We have organized a series of statistical models to see if we could explain the relative populations of single young stars and binaries for all separations in the Perseus molecular cloud, and the only model capable of reproducing the data was one in which all Also form stars initially binary large, “said the researchers.
These systems reduce or dissociate in a million years, said M. Stahler.
In this study, “big” means that the two stars are separated by more than 500 astronomical units (UA) – where a UA is the average distance between the Sun and Earth (about 150 million kilometers).
A large binary companion of our Sun was 17 times farther from the Sun than its farthest planet today, Neptune, they said.
Based on this model, the Sun brothers have probably escaped and mixed with all the other stars in our Milky Way region, never to be looked at, they said.
“According to our simple model, we can say that almost all stars form with a partner,” said Sarah Sadavoy, the Smithsonian Astrophysical Observatory in the United States.
Stars are born in egg-shaped cocoons called dense nuclei, which are prevalent in huge clouds of cold, molecular hydrogen that are breeding young stars.
The researchers mathematically modeled several scenarios to explain this distribution of stars, assuming a typical formation, a rest and the time of orbital contraction.
They came to the conclusion that the only way to explain the observations is to assume that all the stars of the masses around the Sun begin large binary class 0 in dense nuclei in the form of eggs, after which it is 60 percent separated in time. The rest narrows to close binary.