Though not identical, recent evidence shows that it is almost certain that stars are born in pairs, and it also applies to every other sun-like star in the universe. A new analysis by a theoretical physicist from UC Berkeley and a radio astronomer from the Smithsonian Astrophysical Observatory at Harvard University led to this recent finding.
Scientists have long searched for an explanation for this, as many stars actually have companions, including Earth’s nearest neighbour, the Alpha Centauri, which is a triplet system. They want to know if binary and triplet stars are born that way or if stars capture one another. It can even be that binary stars sometimes split up and end up becoming single stars.
In fact, scientists have also looked for a companion to the Sun, which is referred to as Nemesis. Nemesis was supposed to have thrown an asteroid into the planet’s orbit that ended in collision and the extermination of dinosaurs. However, this star has never been found.
The new theory is based on a radio survey of a huge molecular cloud filled with recently formed stars in the constellation Perseus. According to co-author Steven Stahler, a UC Berkeley research astronomer, “we are saying yes, there probably was a Nemesis, a long time ago.” Stahler also adds that they ran a series of “statistical models to see if we could account for the relative populations of young single stars, and binaries of all separations in the Perseus molecular cloud, and the only model that could reproduce the data was one in which all stars form initially as wide binaries.”
The Perseus molecular cloud and other star-forming regions are littered with egg-shaped cocoons known as dense cores, in which new stars are born. The most recent analysis suggests stars born in these dense cores split far apart 60 percent of the time. The other 40 percent of the time, the egg-like cores yield closely linked binaries.
A wide binary companion to our sun would have easily been around 17 times farther from the sun than Neptune. If we were to follow this model, the sun’s pair most likely escaped and combined with all the other stars in our region of the Milky Way galaxy.