New research published in Astronomy & Astrophysics presents the most realistic model of formation for binary star systems. Scientists are working to understand how Tatooine can exist, everyone. Science fiction becomes science fact before our eyes. Sure, we’ve found these systems, so we already knew they’re out there. But how? How did what was surely a chaotic environment for planetary formation manage to work? The researchers looked at the Alpha Centauri system for the answers. 

Alpha Centauri is a binary system where a smaller companion star orbits the larger parent star every 100 years or so, and the larger star would act like a mixer, swirling up any dust in the protoplanetary disc. The researchers then used this system as the basis for their model, and they found that the building blocks for planets, or planetesimals, would need to be orbiting the smaller star and start off at least 10 kilometers in diameter. That disc also needs to be pretty circular for the planets to form. After that, the bits all need to move slowly enough relative to each other to stick together instead of breaking apart in collisions. As those baby planetesimals grow larger, they become less prone to being destroyed in collisions caused by the mixing caused by the larger star. So binary systems can have planets simply by growing them rather than capturing rogue planets moving past. This work is an important piece in all that planetary formation theory we keep talking about. More, please!

More Information

University of Cambridge press release

“Planet formation in stellar binaries: Global simulations of planetesimal growth,” K. Silsbee and R. R. Rafikov, to be published in Astronomy & Astrophysics