Astronomers using Chile’s Atacama Large Millimetre/submillimetre Array (ALMA) have made a groundbreaking discovery that could revolutionise our understanding of planetary formation. In a recent study published in the journal Astronomy & Astrophysics, the researchers reported strong evidence of two exoplanets sharing the same orbit around a young star known as PDS 70, located approximately 400 light-years away from Earth. This is an incredibly rare and fascinating phenomenon that has never been observed before in such detail.
The star PDS 70 is already known to host two Jupiter-like planets, named PDS 70b and PDS 70c. Now, the astronomers have identified a cloud of debris that appears to be sharing the orbit of one of these planets, PDS 70b. This cloud of debris could potentially be the building blocks of a new planet or remnants of one that has already formed. If confirmed, this discovery would represent the strongest evidence yet of two exoplanets co-existing in the same orbital path.
Trojan planets, also known as co-orbital planets, are pairs of planets with similar masses that share the same orbit around their host star. In our own Solar System, a famous example of Trojan bodies exists in the form of the Trojan asteroids associated with Jupiter. These asteroids number more than 12,000 and share Jupiter’s orbit around the Sun.
While astronomers have speculated that such Trojan planets could exist around stars other than our Sun, actual evidence of their existence has been scarce until now. This discovery opens up new avenues of research and poses intriguing questions about the formation, evolution, and prevalence of Trojans in various planetary systems.
Co-author Nuria Huelamo, a senior researcher at the Centre for Astrobiology, explains that this finding is just the beginning of the quest to identify and study co-orbital planets at early stages of their formation. Itziar De Gregorio-Monsalvo, ESO Head of the Office for Science in Chile and another contributor to the research, echoes this sentiment and emphasizes the potential implications for our understanding of planetary dynamics in different systems.
To fully confirm their findings, the research team will continue their observations and plan to use ALMA again after 2026. They aim to closely monitor the movement of both PDS 70b and the associated debris cloud as they orbit the star together. If the two objects indeed move significantly in tandem, it would provide definitive proof of the existence of Trojan planets in this distant star system.
Lead researcher Balsalobre-Ruza expresses excitement about the potential implications of this discovery, stating that it could mark a major breakthrough in the field of exoplanetary research. Furthermore, with the planned improvements in ALMA capabilities scheduled for 2030, astronomers hope to gain deeper insights into the nature and prevalence of Trojan planets in many other stellar systems.
As our understanding of exoplanets and their interactions continues to grow, this latest discovery adds a remarkable chapter to the ongoing saga of planetary exploration. The cosmos never ceases to amaze, and researchers around the world eagerly await further revelations from the stars.
