Astronomers have discovered a rare planetary system that seems straight out of science fiction — three Earth-sized planets orbiting two suns.
The system, called TOI-2267, lies about 190 light-years away, and it’s the first known binary star system where each star hosts at least one planet that passes, or transits, in front of it.
The finding, published in Astronomy & Astrophysics, offers an exciting glimpse into how planets can form and survive in double-star systems — environments once thought too unstable for complex planetary systems.
“This is the first binary system we know of where planets are transiting around both stars,” said Sebastián Zúñiga-Fernández from the University of Liège (ULiège) in Belgium, who led the study.
“It’s a truly unique setup that challenges what we thought we knew about planet formation.”
TOI-2267 is what astronomers call a compact binary system, meaning its two stars orbit each other very closely.
Such systems create powerful gravitational forces that usually make it difficult for planets to form or remain stable.
Yet in this case, scientists found three rocky planets roughly the size of Earth, all orbiting in tight paths around their respective stars.
“This discovery breaks several records,” said Francisco J. Pozuelos of the Instituto de Astrofísica de Andalucía (IAA-CSIC), who co-led the research.
“It’s the most compact and coldest binary star pair with planets ever found, and the first time we’ve seen planets transiting both stars in such a system.”
The discovery began with data from NASA’s TESS space telescope, which scans the sky for tiny dips in starlight caused by planets passing in front of their stars.
Using their custom detection software called SHERLOCK, astronomers from ULiège and IAA-CSIC first spotted hints of two planets. That early find allowed them to organize ground-based follow-up observations before TESS gathered more data.
To confirm that the signals were truly planets, the team conducted an extensive observing campaign with several telescopes, including the SPECULOOS and TRAPPIST observatories—two robotic telescope networks operated by ULiège.
These instruments specialize in detecting small exoplanets around faint, cool stars and played a key role in confirming and characterizing the TOI-2267 system.
Finding three Earth-sized planets in such a challenging environment gives scientists a rare “natural laboratory” for studying how planets form and survive under extreme conditions.
“We used to think planets couldn’t remain stable in systems like this,” said Zúñiga-Fernández. “But now we have proof they can—and that opens up a whole new area of study.”
Future observations with the James Webb Space Telescope (JWST) and next-generation ground telescopes could measure the planets’ masses, densities, and even their atmospheres.
This discovery not only pushes the boundaries of how we understand planet formation but also demonstrates the power of combining space and ground-based observatories to uncover the hidden worlds of our galaxy.
Source: University de Liege.
