Scientists discover 27 potential new planets that orbit two stars in solar systems far, far away | Astronomy

Astronomers have discovered 27 potential new planets orbiting two stars, like the fictional desert planet Tatooine from the Star Wars universe.

To date, only 18 circumbinary planets – which orbit two stars – had been identified in the universe. More than 6,000 planets have been discovered orbiting single stars, such as Earth orbiting the sun.

In a timely release on May 4, also known as Star Wars Day, scientists identified nearly 30 other candidate planets, ranging in distances from 650 to 18,000 light years from Earth.

“There are a lot of things in astronomy that are not very tangible,” said Associate Professor Ben Montet of the University of New South Wales (UNSW), lead author of the study. But thanks to the famous Tatooine sunset scene in the first Star Wars movie, “everyone has an idea of ​​what a circumbinary planet looks like and what it would mean to stand on a planet with two suns.”

More than half of the stars in the universe exist in binary or multiple star systems.

Scientists have already identified circumbinary planets through their transits: When these planets pass in front of a star, Montet said, “it casts a shadow on the surface of the star, we see a drop in the brightness of the star… and we can infer that there is something surrounding it.”

But this only happens when the planet and its star align perfectly with our field of view from Earth. “We’re potentially missing a lot of systems,” Montet said.

“Planets are hard to find. It’s like trying to see a candle right next to a tall lamp post.”

Instead, the researchers used a method known as “absidal precession,” looking for an oscillation between stars that orbit and eclipse each other.

“If we monitor the exact timing of these eclipses… it can tell us that there is something else going on in the system,” said Margo Thornton, lead author of the study and a PhD student at UNSW.

After eliminating other factors such as the rotation and gravitational attraction of the two stars, the team identified 36 out of 1,590 star systems whose behavior could only be explained by a third body.

For “27 of these objects, it’s possible that they have the mass of a planet,” Thornton said. Further research into their spectra – the light they emit – was needed to formally confirm that they are circumbinary planets, she said. “It’s just a question of: How big is it? Is it a planet? Is it a brown dwarf? Is it a star?”

The team discovered the potential planets – which likely range from the size of Neptune to ten times heavier than Jupiter – using data from NASA’s Transiting Exoplanet Survey Satellite, a planet-hunting space telescope launched in 2018.

Dr Sara Webb, an astrophysicist at Swinburne University of Technology who was not involved in the research, said the team’s “very clever techniques” could be used to find more candidate planets in the future.

Circumbinary planets would likely have “very extreme environments,” unlike anything in our solar system, Webb said. “[But] a planet like Tatooine could potentially exist where that sweet spot is between its orbit of the two stars – where it’s neither too hot nor too cold.

“When the first Star Wars came out, we didn’t know exoplanets existed [planets outside our solar system] at all. »

“A lot of things that are predicted in art and in artistic concepts of what the universe might be, we tend to find…also in science.”

The research was published in the Monthly Notices of the Royal Astronomical Society.