A remarkable advancement in the study of exoplanets has led researchers to identify three planets similar in size to Earth orbiting around two stars in a closely bound binary system approximately 190 light-years from Earth. This system, designated TOI-2267, represents the first known case where planets transit each star in a binary pair, challenging previous beliefs regarding planetary stability in such environments.
Published in Astronomy & Astrophysics, this discovery was made by an international collaboration utilizing NASA’s TESS space observatory along with extensive follow-up studies via the SPECULOOS and TRAPPIST telescope arrays. The system features a pair of M-dwarf stars orbiting closely, an arrangement once thought to be hostile to the formation or long-term survival of terrestrial-type planets.
The research team from the University of Liège, which led the project, highlights that TOI-2267’s architecture breaks new ground. Detecting planets crossing in front of both stars in the system revises existing theories that regarded such binary stars as too gravitationally volatile to support compact planetary systems.
Planets Transit Both Stellar Components
In TOI-2267, astronomers observed the transits of planets passing across the disks of both stars, a phenomenon never documented before. Two of the Earth-sized planets orbit one of the stars, while a separate third travels around the other companion. Lead author Sebastián Zúñiga-Fernández from the University of Liège describes the configuration as “unlike any planetary system previously studied.” This distinctive arrangement sets TOI-2267 apart from other binary star systems known so far.
The binary stars themselves are a compact and cool duo. In the view of the Instituto de Astrofísica de Andalucía, TOI-2267 is notably the coldest and most tightly knit stellar pair discovered to host exoplanets. Despite conventional predictions that strong gravitational forces within such a system would disrupt planetary orbits, these three Earth-sized planets maintain stable paths.
Discovered with SHERLOCK and Validated on Earth
Two planets were initially identified using a specialized analysis tool developed by the researchers rather than through the usual TESS data assessment pipeline. This software, called SHERLOCK, enabled scientists at the University of Liège and IAA-CSIC to mine TESS observations for subtle transit signals, paving the way for prompt terrestrial follow-up that confirmed the existence of the planets.
Confirming these findings involved a global cooperative effort, particularly leveraging the SPECULOOS and TRAPPIST robotic telescope networks. Managed by the University of Liège, these facilities specialize in observing faint, cool stars and were instrumental in verifying planetary transits and defining the system’s characteristics.
Co-leader Francisco J. Pozuelos from IAA-CSIC notes, “This detection shatters previous records and exemplifies the first instance of planets transiting both stars of a binary. The synergy between innovative data processing and dedicated observational resources was key in confirming these planets.”
Defying Conventional Wisdom on Binary Star Planets
This discovery contradicts established ideas about planet formation around close binary stars. Prevailing models argue that intense gravitational forces in such systems create chaotic conditions unsuitable for rocky planets to both form and maintain stable orbits. TOI-2267 counters these expectations with clear evidence of stable Earth-sized planets.
“This binary system offers a real-world testing ground,” Zúñiga-Fernández comments. It presents an opportunity to investigate how rocky planets can originate and sustain themselves amid extreme gravitational influences, prompting a reassessment of prior hypotheses about binary star environments.
As outlined in the report from the University of Liège, this finding highlights the valuable combination of space observatories like TESS alongside specialized ground telescopes to advance exoplanet research. TOI-2267 now stands as a prime example of how planetary systems can endure in conditions once believed to be prohibitive.
- Categories:
- Space
0 comments
Sign in to Comment