According to a new analysis by a theoretical physicist from UC Berkley and a radio astronomer from the Smithsonian Astrophysical Observatory at Harvard University, our Sun, as well as every other Sun-like star in the universe, had a twin when it was born.
The new assertion is based on a radio survey of a giant molecular cloud filled with recently formed stars in the constellation Perseus, and a mathematical model that can explain the Perseus observations only if all Sun-like stars are born with a companion. Scientists ran a series of statistical models to see if they 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.’ These systems then either shrink or break apart within a million years.
[In this study, ‘wide’ means that the two stars are separated by more than 500 astronomical units, or AU, where one AU is the average distance between the Sun and Earth - 150 million km. A wide binary companion to our Sun would have been 17 times farther from the Sun than its most distant planet today, Neptune.]
Based on this model, the Sun’s sibling most likely escaped and mixed with all the other stars in our region of the Milky Way galaxy, never to be seen again. The conclusion is that Sun-like stars are not primordial, they are the result of the breakup of binaries.
Readers may also be interested in an associated blog on the ‘Sun’s family:’
Sources/Reference: Source: UC Berkeley. Reference: "Embedded Binaries and Their Dense Cores" - Sarah Sadavoy, Steven W. Stahler - Submitted on April 28, 2017 - Accepted in MNRAS - ArXiv server
Credit for image at top of page: Bill Saxton, ALMA (ESO/NAOJ/NRAO), NRAO/AUI/NSF