Speaking Thursday, a team of astronomers announced they have discovered a pair of new worlds orbiting double-star systems — the real-life incarnations of the fictional planet Tatooine from “Star Wars.”
“This is the most compact system of planets,” said John Johnson, of the California Institute of Technology in Pasadena. “It’s like you have a shrink raygun and set it to seven times smaller and zapped a planetary system.”
Astronomers used NASA’s Kepler space telescope to identify the two so-called “circumbinary planets” amid 750 systems they sampled. Their discovery brings the total number of confirmed double-sun worlds up to three. The team said the planets orbit as pair of suns similar to that seen in “Star Wars.”
Most sunlike stars in our galaxy are found in pairs known as binary systems. Scientists discovered the first planet orbiting a binary star system last year using theKepler space observatory. That circumbinary planet, Kepler-16 b, is located about 200 light-years away.
All the circumbinary planets seen to date are very close to the critical distance when their orbits would be unstable. “If they were only 20 to 25 percent closer to their stars, the gravitational tugs of the two stars would build up over time and eventually make the planet’s orbit so wild that the planet would be ejected into deep space,” Welsh said.
Given the rate of circumbinary planets seen to date, the scientists estimate about 1 percent of closely linked binary stars have giant planets circling around them. This suggests our galaxy is home to at least several million circumbinary planets.
“There are lots of these circumbinary planets — they are not the rare beasts that they might have been,” Welsh said. “That tells us that nature likes to form planets, even in chaotic environments close to two stars.”
“I am going to stay focused on the hunt for more circumbinary planets,” Welsh added. “It’s by no means easy, but I expect we will find more of these gems in the Kepler data.”