SEATTLE, Wash. — Luke Skywalker’s home planet in Star Wars is the stuff of science fiction. Called Tatooine, the planet orbits two stars. A new study suggests similar planets might be the best focus in the search for places that can host life outside our solar system.
Many suns come in pairs called binary stars. Lots of these should have planets orbiting them. That means there could be more planets orbiting around binary stars than around lone stars like our sun. But until now, no one had a clear idea about whether those planets could sustain life. New computer models suggest that in many cases life could imitate Star Wars.
Earthlike planets orbiting some binary stars can stay in stable orbits for at least a billion years. Researchers shared their finding in Seattle, January 11, at the American Astronomical Society meeting. That sort of stability could potentially allow life to develop, as long as the planets aren’t too hot or too cold.
The researchers ran computer models of binary stars arranged in thousands of ways. Each had an Earthlike planet orbiting the two stars. The team varied things like how massive the stars were compared to each other. They modeled different sizes and shapes of the stars’ orbit around each other. And they also looked at the size of the planet’s orbit around each star pair.
The scientists then tracked the motion of the planets for up to a billion years of simulated time. That revealed whether the planets would stay in orbit over timescales that might allow life to emerge.
They also checked to see if the planets stayed in a habitable zone. That’s the region around a star where an orbiting planet’s temperatures are never extremely hot or cold, and water could stay liquid.
The team made models for 4,000 sets of planets and stars. Of those, roughly 500 had stable orbits that kept planets in their habitable zones 80 percent of the time.
Going steady
A planet orbiting binary stars can…
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