A Quirk of Light Reveals the Strangest Planetary System Yet

Just 120 light-years from Earth, astronomers have identified a truly astonishing and one-of-a-kind system in the known universe.

Two Brown Dwarfs and a Planet With a Perpendicular Orbit

It consists of two brown dwarfs orbiting each other in an eclipsing binary configuration, along with an exoplanet that orbits both bodies — but with a fascinating twist: the planet’s orbit is perpendicular, circling the poles of the brown dwarfs.

This marks the first time a planet has been detected in a polar orbit around a binary system — and not just any binary, but an eclipsing pair of brown dwarfs. The system, called 2M1510, is only the second eclipsing brown dwarf binary ever recorded.

“Finding a planet orbiting not just a binary system, but a binary of brown dwarfs — and in a polar orbit — is really incredible and exciting,” says astronomer Amaury Triaud from the University of Birmingham in the UK.

Brown dwarfs are curious celestial bodies, sitting somewhere between stars and planets. They have enough mass to fuse deuterium (a heavier form of hydrogen), but not enough for the regular hydrogen fusion that powers stars. For this reason, they’re sometimes called “failed stars,” though it may be more accurate to see them as the lowest tier on the stellar spectrum.

The Scientific Value of Brown Dwarfs

Studying brown dwarfs can offer valuable clues about how stars and planets form — which is part of what makes this discovery so compelling.

Interestingly, the planet was discovered by accident. Led by astronomer Thomas Baycroft, also from the University of Birmingham, the researchers were analyzing the light emitted by the brown dwarf pair to better understand their properties when they noticed something off: the movement of the brown dwarfs couldn’t be fully explained by their mutual orbit.

Nearby, smaller bodies like planets can slightly tug stars, causing them to wobble and altering the wavelength of the light they emit.Triaud and other scientists have been refining techniques to detect planets in multi-star systems by identifying these small wobbles — and that’s exactly how they spotted something strange in 2M1510.

Detailed Analysis Reveals a Surprise

Further analysis revealed a third body — another brown dwarf — at a much greater distance. But it was too far to be causing the wobble. After running models, the team arrived at a surprising conclusion.

“We evaluated all possible scenarios, and the only one that fits the data is a planet in a polar orbit around the binary,” Baycroft explains.

According to their measurements, the two main brown dwarfs, 2M1510 A and 2M1510 B, each have about 35 times the mass of Jupiter and complete an orbit around each other every 20.9 days. Since they are an eclipsing binary, they pass in front of one another from Earth’s perspective.

The third body, 2M1510 C, is located roughly 250 times the distance between the Earth and the Sun, with an orbital period of about 11,000 years.

The exoplanet, named 2M1510 (AB) b, is still somewhat of a mystery. The researchers estimate that the planet takes between 100 and several thousand days to complete an orbit, and they believe its mass falls somewhere between 10 and 1,000 Earth masses — most likely in the hundreds (for comparison, Jupiter has 318 Earth masses).

Next Steps and Future Possibilities

The team plans to conduct follow-up observations to refine these broad estimates and better understand what’s going on in this strange system. Even with these uncertainties, the discovery is incredibly exciting.

We made the discovery by chance — we didn’t aim our observations at finding a planet, much less one with such a peculiar orbital configuration. It was a big surprise,” Triaud says. “Overall, I think this reminds both us astronomers and the general public of just how fascinating and unpredictable the universe truly is.”

Read the original article on: Science Alert

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