A team of international researchers has identified three Earth-sized planets within the binary star system known as TOI-2267, located approximately 190 light-years from Earth. This groundbreaking discovery, published in the journal Astronomy & Astrophysics, sheds new light on how planets can form and remain stable in a double-star environment, which has traditionally been thought to be unfavorable for complex planetary systems.
According to Sebastián Zúñiga-Fernández, a researcher involved in the study and a member of the ExoTIC group at the University of Liège, “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 known binary system to host transiting planets around both stars.
The compact nature of TOI-2267, characterized by its two closely orbiting stars, creates a gravitationally unstable environment for planet formation. However, the discovery of these three Earth-sized planets in such brief orbits contradicts several long-standing theories about planetary formation. Francisco J. Pozuelos, a former member of the ExoTIC group and now a researcher at the Instituto de Astrofísica de Andalucía, noted, “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.”
The initial identification of two of the three planets was made using data from NASA”s TESS space telescope, while astronomers from the University of Liège and the Instituto de Astrofísica de Andalucía employed their detection software, SHERLOCK, to enhance their findings. This early discovery allowed the team to conduct ground-based follow-up observations ahead of schedule. A comprehensive observational campaign, utilizing multiple observatories, was essential to confirm the planetary signals later.
The SPECULOOS and TRAPPIST telescopes, led by the University of Liège, played a pivotal role in confirming the planets and characterizing the overall system. These robotic telescopes, designed to study small exoplanets around faint, cool stars, were crucial for this research. Zúñiga-Fernández remarked, “Discovering three Earth-sized planets in such a compact binary system is a unique opportunity,” allowing researchers to test the limits of existing planetary formation models and understand the diverse architectures of planets in our galaxy.
Additionally, this discovery opens avenues for further observations with advanced instruments such as the James Webb Space Telescope (JWST) and next-generation ground-based telescopes. These technologies will enable scientists to measure the masses, densities, and potentially the atmospheric compositions of these distant worlds accurately. This remarkable finding not only captivates the imagination but also illustrates the synergy between space missions and specialized ground-based telescopes like SPECULOOS and TRAPPIST in advancing our understanding of exoplanets.
