Astronomers find planets with double sunsets 190 light-years from Earth
By isabelle // 2025-11-13
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  • Astronomers have discovered three Earth-sized planets in a tight binary star system.
  • This finding challenges theories that such systems are too chaotic for planets.
  • The system is the first known with planets transiting both of its stars.
  • The discovery was made using NASA's TESS telescope and confirmed by ground observatories.
  • It provides a new natural laboratory to test planet formation models.
In the vast cosmic ocean, a discovery 190 light-years away is forcing scientists to tear up the old rulebook on how planets form. An international team of astronomers has confirmed the existence of three Earth-sized planets orbiting within a binary star system known as TOI-2267, a finding that directly challenges long-held theories that such twin-star environments are too gravitationally chaotic for complex planetary systems to develop. This revelation, made possible by NASA’s TESS telescope and confirmed by a global network of ground-based observatories, opens a new chapter in the search for worlds beyond our solar system and suggests our galaxy may be far more populated with diverse planets than previously believed. The system itself is a record-breaker. TOI-2267 is what astronomers call a compact binary, meaning its two stars are locked in a tight orbital dance. This proximity creates intense gravitational forces that, according to conventional models, should rip apart the disks of dust and gas that coalesce into planets or fling any newly formed worlds into the void of interstellar space. Yet, against all odds, three rocky worlds have been found there. "Our analysis shows a unique planetary arrangement: two planets are transiting one star, and the third is transiting its companion star," explains Sebastián Zúñiga-Fernández, a researcher at the University of Liège and first author of the paper published in Astronomy & Astrophysics. "This makes TOI-2267 the first binary system known to host transiting planets around both of its stars."

A landmark discovery for astronomy

This is not just another exoplanet discovery. It is a fundamental shift in understanding. For decades, the gravitational turmoil of binary systems was seen as a major barrier to planet formation. This discovery proves that planets can not only form in such environments but can also achieve a stable, multi-planet architecture. The significance is not lost on the researchers involved. "Our discovery breaks several records, as it is the most compact and coldest pair of stars with planets known, and it is also the first in which planets have been recorded transiting around both components," says Francisco J. Pozuelos, a co-leader of the study from the Instituto de Astrofísica de Andalucía. The initial clues came from data collected by NASA’s Transiting Exoplanet Survey Satellite (TESS). Astronomers from the University of Liège and IAA-CSIC used their custom detection software, SHERLOCK, to sift through the TESS data, identifying the tell-tale dips in starlight that hinted at planets crossing in front of, or transiting, their host stars. This potential discovery triggered a major confirmation effort using some of the world's most sensitive ground-based telescopes. The robotic SPECULOOS and TRAPPIST telescopes, designed specifically to study small planets around cool, dim stars, played a pivotal role in verifying the planets and characterizing the system.

A natural laboratory for new theories

With the planets confirmed, TOI-2267 has been transformed from an oddity into a crucial testing ground. It serves as a real-world laboratory to challenge and refine computer models of planet formation. Scientists can now study how rocky worlds emerge and persist under what were once considered prohibitive conditions. "Discovering three Earth-sized planets in such a compact binary system is a unique opportunity," Zúñiga-Fernández notes. "It allows us to test the limits of planet formation models in complex environments and to better understand the diversity of possible planetary architectures in our galaxy." Pozuelos adds a compelling perspective, stating, "This system is a true natural laboratory for understanding how rocky planets can emerge and survive under extreme dynamical conditions, where we previously thought their stability would be compromised." The next steps involve deeper investigation. Powerful instruments like the James Webb Space Telescope are ideally suited to study these distant worlds further. Future observations could determine the planets' masses, densities, and perhaps even the chemical composition of their atmospheres, providing clues about their potential habitability. This discovery is a powerful reminder that the universe is consistently more inventive and resilient than our theories presume. It suggests that planets, including small, rocky ones like our own, may be forming and surviving in a far wider range of cosmic neighborhoods than we ever thought possible. As we continue to look up, we are not just finding new worlds; we are fundamentally redefining the very conditions necessary for a world to exist. Sources for this article include: ScienceDaily.com Space.com PopSci.com
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