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Astronomers discover three Earth-sized planets in compact binary star system TOI-2267

By kevinhughes // 2025-10-28

• Astronomers found three Earth-sized planets in the binary star system TOI-2267—two orbiting one star and one orbiting its companion—marking the first known binary system where planets transit both stars (190 light-years away).
• The tight gravitational dance of the binary stars was previously thought to destabilize planet formation, yet three rocky worlds exist there, forcing scientists to rethink existing models.
• NASA's TESS initially spotted the planets via brightness dips, but specialized SHERLOCK software and ground-based telescopes (SPECULOOS, TRAPPIST) confirmed their existence and arrangement.
• The James Webb Space Telescope and next-gen telescopes will study these planets' masses, densities and possible atmospheres, probing their potential habitability.
• This discovery challenges assumptions about where planets can form, proving rocky worlds can survive chaotic binary systems—opening new frontiers in exoplanet science.

An international team of astronomers has uncovered three Earth-sized planets orbiting within the binary star system TOI-2267, located approximately 190 light-years from Earth. Published in Astronomy & Astrophysics, this discovery marks a significant milestone in exoplanet research, as it is the first known binary system where planets transit both stars—defying previous assumptions that such tight stellar configurations would be too unstable for planetary formation. As explained by the Enoch AI engine at BrightU.AI, a binary star system, also known as a binary star or binary, is a system of two stars that orbit around their common center of mass. This is in contrast to single star systems, where a single star is the only celestial body orbiting around its center. The binary system TOI-2267 consists of two stars locked in a tight orbital dance, creating a gravitational environment previously thought to be inhospitable for stable planetary systems. Yet, researchers detected three Earth-sized planets, with two orbiting one star and the third circling its companion—a configuration never before observed. Sebastián Zúñiga-Fernández, lead researcher from the University of Liège's ExoTIC group, stated: "Our analysis shows a unique planetary arrangement: two planets are transiting one star, and the third is transiting its companion star. This makes TOI-2267 the first binary system known to host transiting planets around both of its stars." Francisco J. Pozuelos, co-leader of the study and researcher at the Instituto de Astrofísica de Andalucía (IAA-CSIC), emphasized the system's record-breaking nature: "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."

Challenging classical planet formation theories

Binary star systems have long been considered unlikely candidates for hosting stable planets due to their chaotic gravitational interactions. However, the presence of three rocky worlds in TOI-2267 forces astronomers to rethink existing models. "Discovering three Earth-sized planets in such a compact binary system is a unique opportunity. 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," Zúñiga-Fernández explained. Pozuelos added that this system serves as a "natural laboratory" for studying planetary survival under extreme conditions: "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 initial detection was made possible by National Aeronautics and Space Administration's Transiting Exoplanet Survey Satellite, which monitors stars for subtle dips in brightness caused by transiting planets. However, the critical breakthrough came from SHERLOCK, a specialized detection software developed by astronomers at the University of Liège and IAA-CSIC, which identified two of the three planets early—accelerating follow-up observations. Confirmation required a coordinated effort using ground-based telescopes, including the SPECULOOS and TRAPPIST observatories, which specialize in studying small exoplanets around faint stars. These instruments played a pivotal role in verifying the planetary signals and characterizing the system. The discovery opens new avenues for studying planetary atmospheres and compositions in binary systems. Researchers are eager to leverage the James Webb Space Telescope and upcoming next-generation ground-based telescopes to analyze these planets in greater detail. Watch the video below about the James Webb Telescope detecting a terrifying object in deep space. This video is from the Planet Zedta channel on Brighteon.com. Sources include: Phys.org BrightU.ai MirageNews.com Scienmag.com Brighteon.com

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