Everyone has a picture of what a circumbinary planet looks like
On the day the galaxy far, far away is celebrated, astronomers have offered the cosmos something more grounding than myth: evidence that worlds orbiting twin suns are not the invention of storytellers, but a quiet feature of the universe itself. A team from the University of New South Wales has identified 27 candidate planets circling binary star systems between 650 and 18,000 light-years from Earth, more than doubling the known population of such worlds through a novel method that listens for gravitational whispers rather than waiting for shadows to fall. The discovery reminds us that our instruments are still learning to hear what the universe has long been saying — and that imagination, more than once, has arrived at truth before the telescope.
- Only 18 circumbinary planets had ever been confirmed; this single study adds 27 candidates, fundamentally reshaping what astronomers thought they knew about how common twin-sun worlds might be.
- The traditional detection method — watching for a planet to dim starlight as it passes — requires near-perfect geometric alignment, meaning vast numbers of these worlds have likely been invisible to us all along.
- Researchers pivoted to a subtler signal: gravitational tugs that cause the eclipse timing between two paired stars to shift, a technique called apsidal precession detection applied across 1,590 binary systems from NASA's TESS satellite.
- Of 36 systems showing unexplained orbital behavior, 27 carry signatures consistent with planetary mass — though spectral analysis is still needed to rule out brown dwarfs or faint stellar companions.
- If this method scales, thousands more circumbinary planets may be hiding in existing data, and some could occupy habitable zones where the balance of two suns might, against all odds, support life.
On May 4th — the day Star Wars fans claim as their own — astronomers announced that Luke Skywalker's twin-sunset world is less fiction than it once seemed. Researchers at the University of New South Wales have identified 27 candidate planets orbiting binary star systems, more than doubling the roughly 18 circumbinary planets previously confirmed to exist anywhere in the cosmos. The candidates lie between 650 and 18,000 light-years away, scattered across the galaxy in systems most of us will never directly observe.
What sets this discovery apart is not just its scale but its method. For years, circumbinary planets were found by watching for the dimming of starlight when a planet transits its host stars — a technique that only works when the geometry aligns perfectly from Earth's vantage point. Lead researcher Ben Montet described the limitation plainly: finding a planet this way is like trying to spot a candle beside a streetlight. His team, including lead author Margo Thornton, instead searched for gravitational wobbles — subtle shifts in the eclipse timing between paired stars caused by a third orbiting body. Sifting through data from NASA's TESS satellite across 1,590 binary systems, they found 36 with unexplained orbital behavior, 27 of which showed signatures consistent with planetary mass.
Confirmation still requires spectral analysis to determine whether each candidate is truly a planet, a brown dwarf, or something else entirely. The objects likely range from Neptune-sized worlds to bodies ten times more massive than Jupiter. Astrophysicist Sara Webb, who was not involved in the study, noted that such worlds would exist in extreme environments unlike anything in our solar system — yet a habitable "sweet spot" between two stars could theoretically support life.
What Webb found most striking was how science has closed the distance to imagination. When the original Star Wars was released, no exoplanets had been confirmed at all. Now, a method capable of finding 27 candidates from a sample of 1,590 systems suggests thousands more twin-sun worlds may be hiding in data already collected — waiting, as they always have been, to be heard.
On the calendar day that Star Wars fans celebrate their universe, astronomers announced something that would have seemed purely fictional just decades ago: they have found evidence of 27 new worlds orbiting not one star, but two. The discovery more than doubles the known population of circumbinary planets—those rare celestial bodies that dance around paired suns rather than solitary ones. Until now, only about 18 such planets had been confirmed to exist anywhere in the cosmos. More than 6,000 planets have been found orbiting single stars like ours, but the twin-star variety remains exotic, distant, almost theoretical.
The candidates themselves are far away. They range from 650 to 18,000 light-years from Earth, scattered across the galaxy in systems that most of us will never see directly. What makes the discovery significant is not just the number, but the method. For years, astronomers found circumbinary planets the traditional way: watching for the telltale dimming of starlight when a planet passes in front of its host stars. It works, but only when the geometry aligns perfectly from our vantage point on Earth. "We're missing lots of systems, potentially," said Ben Montet, a researcher at the University of New South Wales who led the study. "Planets are hard to find. It's like trying to see a candle right next to a big street light."
Montet and his team, including lead author Margo Thornton, took a different approach. Instead of looking for shadows cast by planets, they searched for wobbles—subtle shifts in the timing of eclipses between the two stars themselves. When a third body, a planet, orbits nearby, its gravity tugs at the binary pair, causing their eclipse patterns to shift in measurable ways. The researchers sifted through data from 1,590 binary star systems collected by NASA's Transiting Exoplanet Survey Satellite, a space telescope launched in 2018. After accounting for the stars' own rotation and gravitational effects on each other, they identified 36 systems whose behavior could only be explained by something else orbiting there. In 27 of those cases, the evidence pointed to objects massive enough to be planets.
Thornton emphasized that confirmation still requires more work. Astronomers need to measure the light these objects emit to determine their true mass and nature. "It's just a matter of: what is the mass of it? Is it a planet? Is it a brown dwarf? Is it a star?" she said. The candidates likely range from Neptune-sized worlds to objects ten times heavier than Jupiter—a spectrum of possibilities that underscores how much remains unknown about these distant systems.
The timing of the announcement, released on May 4th—Star Wars Day—was not accidental. The fictional planet Tatooine, Luke Skywalker's desert home with its famous double sunset, has become the cultural touchstone for what a circumbinary world might look like. Ben Montet noted the power of that image: "Everyone has a picture of what a circumbinary planet looks like and what would it mean to stand on a planet with two suns." Sara Webb, an astrophysicist at Swinburne University of Technology who was not part of the research, observed that such worlds would exist in "very extreme environments" unlike anything in our solar system. Yet she also noted that a habitable zone could theoretically exist in the space between the two stars—a "sweet spot" where temperatures might support life, neither scorched nor frozen.
What strikes Webb most is how science has caught up to imagination. "When the original Star Wars was released, we didn't know that there were exoplanets at all," she said. "A lot of things that are predicted in art and in artistic concepts of what the universe might be, we tend to find it in science as well." The new detection method opens a path forward. If apsidal precession can reveal 27 candidates from a sample of 1,590 systems, the technique could unlock thousands more circumbinary planets hiding in existing data and future observations. The universe, it seems, has been writing science fiction all along.
Citas Notables
Planets are hard to find. It's like trying to see a candle right next to a big street light.— Ben Montet, University of New South Wales
A lot of things that are predicted in art and in artistic concepts of what the universe might be, we tend to find it in science as well.— Sara Webb, Swinburne University of Technology
La Conversación del Hearth Otra perspectiva de la historia
Why does finding planets around two stars matter more than finding them around one?
Because more than half the stars in the universe exist in binary systems. If we only look for planets around single stars, we're ignoring most of the galaxy. These worlds could be common, but we've been blind to them.
The method sounds clever—watching for wobbles instead of shadows. Why is that harder to do than just looking for dimming?
It's not harder, exactly. It's different. The shadow method only works when the planet, its stars, and Earth line up perfectly. Wobbles happen regardless of our angle. You're listening to the gravity itself rather than waiting for a specific view.
So these 27 candidates—are they confirmed planets or not?
Not yet. They're strong candidates. The gravity signatures are real. But to know if something is a planet versus a brown dwarf or a small star, you need to measure its mass precisely. That requires analyzing the light it gives off, which is harder when it's so far away and so faint.
Could any of them actually be habitable?
Theoretically, yes. You'd need a zone between the two stars where it's warm enough but not too hot. The environments would be extreme—nothing like Earth. But the physics allows for it. That's what makes Tatooine not just fantasy.
Why announce this on Star Wars Day specifically?
Because the image of a double sunset on an alien world has been in people's minds for fifty years. Now we know those worlds probably exist. It's a moment where science catches up to what artists imagined.
What happens next?
More observations. Better telescopes. The technique they used could find thousands more candidates if applied systematically. We're at the beginning of understanding how common these worlds really are.