The Sun's "evil" twin is probably lurking beyond the Solar System—Michael Irving, New Atlas
Since the 1980s, astronomers have been searching for the Sun's "evil" twin, dubbed Nemesis due to its habit of slinging deadly asteroids our way every 26 million years or so. Lately, the Nemesis hypothesis has fallen out of favor after decades of sky surveys have turned up no trace of the star, but a new mathematical model from UC Berkeley suggests that almost every star is born with a buddy – including our Sun.
That means that even though the hypothetical Nemesis has never been detected, the Sun probably does have a long-lost twin, which has since migrated out into the Milky Way – it probably isn't evil, though.
"We are saying, yes, there probably was a Nemesis, a long time ago," says Steven Stahler, co-author of the study. "We 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. These systems then either shrink or break apart within a million years."