An international team of scientists has unveiled the discovery of three Earth-sized planets orbiting the binary star system known as TOI-2267, located around 190 light-years from our planet. This significant finding, published in the journal Astronomy & Astrophysics, sheds light on the formation and stability of planets in double-star systems, environments previously deemed too chaotic for supporting complex planetary structures.
“Our analysis reveals a distinctive planetary configuration: two planets transit one star while the third transits its companion star,” stated Sebastián Zúñiga-Fernández, a researcher from the University of Liège and the study”s lead author. “This positions TOI-2267 as the first known binary system to host transiting planets around both stars.”
The peculiar system comprises two stars that are closely bound together in a compact orbit, creating conditions that typically hinder planet formation. Nevertheless, astronomers identified three small, rocky planets that revolve around these stars in tight orbits with short periods. This discovery contradicts longstanding theories about planetary development in such dynamically unstable environments, suggesting that nature may indeed devise ways to establish and sustain planetary systems even under extreme conditions.
“Our findings break multiple records, as this is the most compact and coldest star pair known to host planets, and it is also the first instance where planets are observed transiting both components,” explained Francisco J. Pozuelos, a former member of the ExoTIC group who is currently a researcher at the Instituto de Astrofísica de Andalucía and co-leader of the research.
This discovery is a result of a collaborative international effort. While NASA“s TESS space telescope provided the foundational data, the initial identification of two of the three planets was made by astronomers from the University of Liège and IAA-CSIC using their proprietary detection software, SHERLOCK. This early identification enabled the team to initiate ground-based follow-up observations promptly. The confirmation of these planetary signals necessitated a rigorous observational campaign involving several observatories, including the SPECULOOS and TRAPPIST telescopes, which were pivotal in verifying the existence of these planets and characterizing the system.
“The discovery of three Earth-sized planets in such a compact binary system presents a unique opportunity,” noted Zúniga-Fernández. “It allows us to evaluate the limitations of planet formation models within complex environments and enhances our understanding of the diverse planetary architectures that may exist in our galaxy.” Pozuelos added, “This system serves as a natural laboratory for exploring how rocky planets can form and endure in extreme dynamical conditions, which we previously believed would compromise their stability.”
This groundbreaking discovery raises numerous questions regarding planet formation in binary systems and opens the door for future research, especially with advanced instruments like the James Webb Space Telescope and next-generation ground-based telescopes. These tools will allow for precise measurements of the masses, densities, and potentially the atmospheric compositions of these distant exoplanets. Overall, this finding underscores the effective combination of space missions and specialized ground-based telescopes, such as SPECULOOS and TRAPPIST, in advancing the field of exoplanetary science.
