Astronomers have spotted signs of 27 possible planets circling pairs of stars. These candidate worlds would experience two suns rising and setting in their skies. The finds come from a fresh look at data gathered by NASA’s Transiting Exoplanet Survey Satellite.
Only about 18 circumbinary planets had been confirmed before. That number sits against more than 6,000 known exoplanets found mostly around single stars. The new candidates could more than double the catalog. But they remain unverified for now. Follow-up work will decide which ones hold up.
The technique relies on something called apsidal precession. Binary stars in eclipsing systems take turns blocking each other’s light from our view. Their eclipse timings shift over months and years. Gravitational pulls from an unseen third body can explain some of those drifts. So can tides between the stars themselves or effects from general relativity. Researchers built models to subtract those known influences. What remained pointed to planets in 27 cases.
CNET reported on the study led by University of New South Wales astronomers. Margo Thornton, the Ph.D. candidate who headed the effort, put it plainly. “These are planets every previous survey was blind to.” Her team examined 1,590 eclipsing binaries with at least two years of TESS observations. The systems lie between 650 and 18,000 light-years away.
Some of the candidate planets may weigh less than Jupiter. Others could tip the scales at up to 10 times that mass. A few might sit as low as 12 Earth masses. The spread excites theorists. Planet formation around binary stars has long posed puzzles. Disks of gas and dust around twin stars behave differently than those around solitary ones. Yet here sit possible worlds that managed to assemble and survive.
NASA highlighted the work in its own release. “Identifying transits in binary systems clearly is challenging, but we’d like to know more about the range of planets that can form around two gravitationally bound stars,” Thornton told them. The method sidesteps a key limit of transit searches. Those demand that a planet’s orbit lines up edge-on with Earth. This timing approach works at many inclinations. “Our method doesn’t have that restriction. It can find planets orbiting at all kinds of angles.”
Benjamin Montet, a co-author and associate professor at UNSW Sydney, expressed surprise at the early haul. “I wasn’t expecting to find 27 already at this point from the pilot study.” The result suggests such planets may appear in roughly 2 percent of suitable binary systems. That rate implies many more wait to be found. NASA’s TESS page notes the mission has now driven discoveries beyond its original transit focus. Allison Youngblood, TESS project scientist at Goddard Space Flight Center, welcomed the expansion. “It’s great to see how the same measurements are driving discoveries far beyond its original mission.”
Confirmation won’t come easily. Astronomers will need precise radial velocity measurements from ground-based telescopes. Those velocity wobbles in the stars’ spectra could reveal the planets’ masses directly. Additional TESS data and perhaps observations from the retired Kepler telescope might help too. Some signals could turn out to stem from brown dwarfs or small stars instead. Distinguishing them matters.
The discovery landed on May 4. Star Wars fans instantly noticed the timing. Tatooine, Luke Skywalker’s desert home, circled a binary pair. Real versions of those worlds have captured imaginations since Kepler-16b turned up in 2011. That confirmed planet orbits two stars every 229 days. Its discovery proved such systems could host stable orbits. A handful more followed from Kepler and early TESS finds. Now this batch arrives all at once.
Thornton captured the thrill of first knowledge. “There’s a strange and wonderful feeling that comes with discovery: for a brief window, we were the only people on Earth who knew these planet candidates existed.” She added in comments to Sci.News, “Most of our current knowledge on planets is biased, based on how we’ve looked for them. We’ve mostly found the easiest ones to detect. This new method could help us uncover a large population of hidden planets.”
The work appears in Monthly Notices of the Royal Astronomical Society. It builds on earlier efforts that used similar timing variations but never scaled them this broadly. Previous circumbinary detections relied heavily on seeing planetary transits across one or both stars. Those events grow complicated in binary systems. The stars eclipse each other. Light curves turn messy. Planets can transit at odd intervals or miss detection entirely if their orbits tilt away.
So the new approach opens fresh territory. It probes systems where transits never happen from our vantage. And it does so with data already collected. TESS continues to scan the sky in its extended mission. More eclipsing binaries will accumulate longer baselines. Those extended timelines sharpen the precession signals. Future candidates should emerge with even greater confidence.
Implications stretch beyond counting worlds. Binary stars dominate the galactic stellar population. About half of sun-like stars have companions. If planets form readily in those environments, the total number of habitable zones could rise sharply. Yet stability questions linger. Gravitational tugs between the two stars can fling developing planets outward or destabilize their orbits. The fact that at least some survive offers hope.
Recent related findings add context. A separate April 2026 paper explored semi-automated transit searches in TESS eclipsing binaries and recovered known circumbinary worlds at high rates. That work, published in the same journal, complements the precession method. Together they suggest the true population may exceed what transit surveys alone revealed. The Guardian covered the May announcement, noting the doubling of candidates and the cultural tie to Star Wars Day.
Astronomers now face the task of sorting real planets from false alarms. Some candidates may prove too massive to qualify as planets. Others could align with known stellar companions missed in earlier catalogs. The mass range spans from Neptune-like to super-Jovian. That variety will test formation models. Did these worlds coalesce in a circumbinary disk? Or did they form farther out and migrate inward?
The TESS data set grows richer each year. Its full-frame images capture thousands more eclipsing systems. Applying the same pipeline could yield dozens or hundreds more candidates. Confirmation campaigns will stretch across observatories worldwide. Radial velocity instruments like ESPRESSO or future extremely large telescopes will play key roles. Space-based photometry from missions still in development may add transit detections for the lucky alignments.
For now the 27 stand as promising hints. They remind researchers that detection biases shape our view of the galaxy. What seems rare may simply hide from common techniques. Expand the toolkit, and the universe reveals more of itself. Thornton’s team has done exactly that. They turned eclipse timing into a planet-hunting instrument. The first results look productive. The next steps will determine how many of those distant twin-sun worlds actually exist.
Planet formation theories gain new test cases either way. If most candidates hold up, circumbinary systems become standard stops on the exoplanet map. If many fall away, the survival rate in such chaotic environments drops. Either outcome sharpens models of disk dynamics, migration, and stability. And it all started with watching two stars dance in front of each other, over and over, across years of satellite data.
The hunt continues. New papers will follow. More candidates will appear. Some will earn full confirmation and names. Their atmospheres, if any, may one day yield to spectroscopy. For the moment the discovery stands as proof of concept. Apsidal precession works at scale. Hidden planets no longer stay quite so hidden.
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