In Brief
Scientists believe that most, if not all, sun-like stars are born with a twin. Evidence also suggests that our solar system's sun's twin may be responsible for knocking the comet that killed the dinosaurs toward Earth.

Stellar Doppelganger

We have long known that the dinosaurs were killed by a catastrophic comet impact with the Earth’s surface but what if there was some foul play afoot? Astronomers have discovered that our sun may have been born with a twin, and an evil one, at that. One hypothesis states that every 27 million years, the evil twin, aptly dubbed Nemesis, returns to wreck havoc on the solar system. They believe that the star lobs a few meteors in our direction as it makes its may through the outer limits of the solar system.

Research has lead scientists to believe that most stars are born with at least one sibling. According to UC Berkeley astronomer Steven Stahler, “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.”

Image: NASA, ESA and J. Muzerolle, STScI
Image Credit: NASA, ESA and J. Muzerolle, STScI

Making Stars

These findings could have implications for our understanding of how stars are formed. Looking into how they maintain or break those familial relationships will give us a deeper understanding of how our Universe came to be what it is today. Stahler said, “Our work is a step forward in understanding both how binaries form and also the role that binaries play in early stellar evolution.” Stahler also pointed out that this could even lead to a better understanding of how galaxies are formed.

These findings were made possible by the VLA nascent disk and multiplicity survey (VANDAM) which took a census of a group of baby stars merely a half-million years old. Their findings have been accepted for publication in the Monthly Notices of the Royal Astronomical Society and can be read pre-publication at