Planet’s Strange Orbit Gives Astronomers ‘Big Surprise’

In a real-life twist on Star Wars’ Tatooine—a harsh desert planet with twin suns and a criminal underbelly—astronomers have found a bizarre new world that orbits two stars at a perfect right angle.

For the first time, scientists have found strong evidence of a “polar planet”—a planet whose orbit is tilted at 90 degrees compared to the orbit of its two host stars. The discovery, made using the world’s biggest eye, the European Southern Observatory’s Very Large Telescope (VLT) in Chile.

“This is the first time we’ve had convincing evidence of a planet in this kind of unusual orbit,” said Thomas Baycroft, a PhD student at the University of Birmingham in the U.K. and the lead author of the new study, which was published in Science Advances.

He told Newsweek: “Not many planets orbiting binary stars are known, but they are thought to be common—just difficult to detect. It has actually been predicted that polar orbiting planets around binary stars exist, though none has been confirmed yet.

“The most unexpected result here is that we find evidence of such an orbit around a binary brown dwarf. These objects are rare, so that the best evidence yet of a polar circumbinary planet is in such a rare system is either a stroke of luck or evidence that these rare systems are more interesting than we had thought.”

The unprecedented exoplanet, named 2M1510 (AB) b, orbits a pair of brown dwarfs—celestial bodies larger than gas giants like Jupiter but not massive enough to sustain hydrogen fusion like typical stars. What’s truly groundbreaking is the way it orbits: not in the same plane as the stars’ orbit, but perpendicularly—in a so-called polar orbit.

To picture this, imagine two stars orbiting each other in a flat plane, like spinning wheels. Most known planets orbit along that same flat path. But this planet follows a unique trajectory—looping over the top and bottom of the star pair, more like a hula hoop being spun vertically rather than flat.

Though such orbits have been theorized and planet-forming discs in polar alignment have been spotted, no planet had ever been caught in the act—until now.

The host stars, known as 2M1510, are not ordinary either. They are one of only two known eclipsing brown dwarf binaries, meaning they pass in front of one another from our point of view, causing regular dips in brightness. The system was first identified in 2018 by co-author Amaury Triaud and others using SPECULOOS, a telescope network at Chile’s Paranal Observatory.

The planet’s discovery came as a surprise while the team was using a different instrument—UVES on the Very Large Telescope—to refine measurements of the stars’ motion. Subtle irregularities in how the brown dwarfs moved hinted that something unseen was tugging on them—something in an unusual orbit.

“We reviewed all possible scenarios, and the only one consistent with the data is if a planet is on a polar orbit about this binary,” said Baycroft.

“A planet orbiting not just a binary, but a binary brown dwarf, as well as being on a polar orbit is rather incredible and exciting,” said Triaud.

And it was pure chance that they found it at all. “The discovery was serendipitous… As such, it is a big surprise,” Triaud added. “Overall, I think this shows to us astronomers, but also to the public at large, what is possible in the fascinating u`niverse we inhabit.”

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Reference

Baycroft, T. A., Sairam, L., Triaud, A. H. M. J., & Correia, A. C. M. (2025). Evidence for a polar circumbinary exoplanet orbiting a pair of eclipsing brown dwarfs. Science Advances, 11(16). https://doi.org/10.1126/sciadv.adu0627