Big Surprise: Astronomers Discover First Strong Evidence of a Polar Orbit Exoplanet Around a Binary Star System

Image Credentials: Image Title: Big Surprise: Astronomers Discover First Strong Evidence of a Polar Orbit Exoplanet Around a Binary Star System Source: AI-Generated Image (Aiease.ai) Date: April 2025 Attribution: Created by AI-generated imagery (Aiease.ai), and it does not depict a real-world scene.

Date: April 16, 2025
Source: European Southern Observatory (ESO)

In a groundbreaking discovery, astronomers have found the first strong evidence of a planet orbiting a rare pair of stars at a striking 90-degree angle — a configuration known as a polar orbit. This discovery, made using the European Southern Observatory’s Very Large Telescope (VLT) at Paranal Observatory, Chile, marks a major milestone in exoplanetary research.

The newly identified planet, named 2M1510 (AB) b, orbits around a binary brown dwarf system — two objects larger than gas giants but too small to ignite as stars. These two brown dwarfs form an eclipsing binary, meaning they pass in front of one another as seen from Earth, allowing precise measurements of their movements.

Discovery of 2M1510 (AB) b, a Tatooine-like planet orbiting two brown dwarfs at a 90-degree angle. It’s the first strong evidence of a "polar planet" in a binary system, called "incredible" by experts. The find was serendipitous, as observations weren’t aimed at such a discovery pic.twitter.com/bLdPPbgaNi

— Xirtam (@ISpyCrazies) April 16, 2025

Until now, planets orbiting two stars, like the famous fictional world of Tatooine in Star Wars, have been discovered with orbits closely aligned to the plane of their host stars’ motion. Although planet-forming discs on polar orbits had been observed, direct evidence of planets maintaining such extreme orbital paths was lacking — until today.

“I am particularly excited to be involved in detecting credible evidence that this configuration exists,” said Thomas Baycroft, a PhD student at the University of Birmingham, UK, and the lead author of the study published in Science Advances.

The discovery came as a complete surprise. The research team initially set out to refine the orbital and physical characteristics of the brown dwarf pair 2M1510, using high-precision data from the Ultraviolet and Visual Echelle Spectrograph (UVES) instrument on the VLT. However, subtle, irregular motions in the stars’ orbits suggested the gravitational influence of an unseen companion.

After rigorous analysis of alternative scenarios, the team concluded that the only explanation consistent with their observations was the presence of a planet on a polar orbit around the binary.

“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 Professor Amaury Triaud of the University of Birmingham, who co-authored the study.

This system, only the second known eclipsing brown dwarf binary ever discovered, now also hosts the first known exoplanet in a perpendicular orbit around such a pair — an extremely rare and exotic configuration.

The findings highlight the unexpected diversity of planetary systems in our universe and open new questions about the formation and stability of planets in such extreme environments.

“The discovery was serendipitous, in the sense that our observations were not collected to seek such a planet, or orbital configuration. As such, it is a big surprise,” added Triaud. “Overall, I think this shows us astronomers, but also to the public at large, what is possible in the fascinating Universe we inhabit.”

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