A remarkable discovery has been made by an international team of scientists, who have identified three Earth-sized planets orbiting the binary star system known as TOI-2267. This system is located approximately 190 light-years from Earth. The findings, which challenge long-held assumptions about the formation and stability of planets in binary star systems, were published in the journal Astronomy & Astrophysics.
According to Sebastián Zúniga-Fernández, a researcher at the University of Liège and the study”s lead author, the planetary configuration is unprecedented. “Our analysis shows a unique planetary arrangement: two planets are transiting one star, and the third is transiting its companion star,” he stated. “This makes TOI-2267 the first binary system known to host transiting planets around both of its stars.”
The TOI-2267 system is characterized as a compact binary, with its two stars orbiting closely to one another, creating a gravitationally unstable environment for planet formation. Despite this, the research team has uncovered evidence of three Earth-sized planets in relatively short orbits, which raises significant questions about traditional planetary formation theories. Francisco J. Pozuelos, a co-leader of the study and researcher at the Instituto de Astrofísica de Andalucía, highlighted the importance of this discovery, noting, “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 data for this groundbreaking research was gathered using NASA”s TESS space telescope. However, astronomers from the University of Liège and the Instituto de Astrofísica de Andalucía employed their proprietary detection software known as SHERLOCK to initially identify two of the three planets. This early detection allowed the team to commence follow-up observations from the ground ahead of schedule.
A comprehensive campaign that involved multiple observatories was essential to confirm the planetary nature of the signals detected. The efforts were significantly supported by robotic telescopes such as the SPECULOOS and TRAPPIST, which are designed specifically for studying small exoplanets around dim, cool stars. Zúniga-Fernández remarked, “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.”
This discovery not only paves the way for new observations, particularly with the James Webb Space Telescope and the next generation of large ground-based telescopes, but also poses numerous questions about how planets form in binary systems. These advanced tools will enable scientists to accurately assess the masses, densities, and potentially the atmospheric compositions of these distant worlds.
Ultimately, this finding highlights the potential of combining space missions with specialized ground-based observatories like SPECULOOS and TRAPPIST to push the boundaries of exoplanetary research.
