When you think of iconic movie moments, Luke Skywalker looking at a double sunset comes to mind. But did you know that real planets orbiting two stars exist in our Milky Way? Surprisingly, scientists have found far fewer of these planets than expected, and new research is shedding light on why.
In our galaxy, about 10% of single-star systems host planets. So, researchers thought that the same percentage would apply to the 3,000 known systems with two stars. However, among over 6,000 confirmed exoplanets, only 14 have been discovered orbiting binary stars.
Researchers from the University of California, Berkeley, and the American University of Beirut have a potential explanation. They suggest that Albert Einstein’s theory of general relativity might play a key role. In binary systems, two stars orbit each other in spacious orbits. A planet caught between them feels the gravitational pull from both, which can complicate its orbit.
This gravitational dance causes the planet’s orbit to change over time, a phenomenon called precession. At the same time, the stars’ own orbits are also swinging due to gravity. Over time, their gravitational interactions can pull the stars closer together. This can further affect the planetary orbits, sometimes leading them to become unstable.
Mohammad Farhat, the lead author of the study, explains, “When the orbital paths of the stars and the planets misalign, it can stretch the planet’s path to a breaking point. It may either get too close and be ripped apart, or get thrown out of the system entirely.”
This instability is especially prevalent in tight binary systems, where the stars orbit each other within a week. These are precisely the systems that missions like NASA’s Kepler and TESS often study. They detect planets by observing changes in starlight as planets pass in front of them. This focus might partly explain why we see so few of these unique circumbinary planets.
While it may seem there are only a handful of such planets, researchers believe there could be many more out there. Expert opinions suggest that ongoing advancements in telescopes and detection methods may soon change our understanding. It’s a reminder that the universe is vast and often hides more than we can see.
For more detailed information, you can check out the study published in The Astrophysical Journal Letters on December 8, 2025.
