Astronomers Discover Possible “Sibling” Orbiting Jupiter-like Planet
Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile may have made a groundbreaking discovery in the study of exoplanets. They may have found a rare “sibling” planet that shares the same orbit as a Jupiter-like planet around a young star.
The researchers observed the PDS 70 system, located 370 light-years away in the Centaurus constellation, and found two Jupiter-like planets, known as PDS 70b and PDS 70c, already orbiting the star. However, they also noticed a cloud of debris within the orbital path of PDS 70b, which could indicate the presence of another planet actively forming or already formed.
This direct image of the possible “sibling” planet is believed to be the strongest evidence to date showing that two exoplanets can share the exact same orbit. The findings were detailed in a study published in the journal Astronomy & Astrophysics.
Lead study author Olga Balsalobre-Ruza, a postdoctoral student of astrophysics at Madrid’s Centre for Astrobiology, stated, “Two decades ago, it was predicted in theory that pairs of planets of similar mass may share the same orbit around their star, the so-called Trojan or co-orbital planets. For the first time, we have found evidence in favor of that idea.”
Trojan planets are rocky bodies that exist within the same orbit as planets. While they are common in our solar system, including in Earth’s orbit and Jupiter’s orbit, evidence for Trojan planets beyond our solar system has been sparse. The discovery in the PDS 70 system has caused researchers to question how Trojans form and evolve and how many could exist in other planetary systems.
During their observations, the research team noticed a debris cloud at a point in PDS 70b’s orbit where Trojans might exist. This cloud of debris, with a mass of about twice that of our moon, could potentially be a Trojan planet or a planet in formation.
The researchers will have to wait until after 2026 to confirm the existence of a true Trojan world. They will use ALMA to track the progress of PDS 70b and the debris cloud in their long orbital period around the star.
If confirmed, this discovery would be a breakthrough in the study of exoplanets. It raises questions about the possibility of planets sharing the same orbit and the conditions for habitability. Balsalobre-Ruza said, “Who could imagine two worlds that share the duration of the year and the habitability conditions? Our work is the first evidence that this kind of world could exist.”
Further research and observations will be conducted to shed more light on the mysteries of Trojan planets and their presence in other planetary systems.