Cambridge, England — Astronomers have long speculated about the existence of a mysterious, massive object lurking in the distant reaches of our Solar System. A recent study led by Terry Long Phan and colleagues aims to shed light on this intriguing mystery, potentially identifying a candidate for the theorized “Planet Nine.”
The Solar System presents a complex arrangement of celestial bodies bound by the Sun’s gravity, yet it may hold secrets far beyond the known planets. The hypothesis of Planet Nine originated in 2016 when astronomers Konstantin Batygin and Mike Brown observed peculiar clustering in the orbits of several trans-Neptunian objects (TNOs). These distant entities may be influenced by the gravitational pull of an unseen giant, estimated to be significantly larger than Earth and located well past the orbit of Pluto.
Despite years of exhaustive searches using sophisticated telescopes, this enigmatic planet has remained elusive. Previous efforts to locate it have not produced direct observations, prompting scientists to refine their predictive models. The complexity of identifying such a distant object has only heightened the intrigue surrounding its existence.
In their recent research, Phan and his team adopted a novel strategy by utilizing data from two major infrared surveys conducted years apart: the Infrared Astronomical Satellite (IRAS) and the AKARI mission. The significant time gap allowed researchers to track slow-moving bodies, expected to drift about 3 arcminutes annually. This distinctive movement aligns with models forecasting the behavior of a massive, distant planet.
The researchers meticulously employed the AKARI Far-Infrared Monthly Unconfirmed Source List, a resource tailored to identify faint, moving objects, allowing them to exclude brighter sources. They estimated the characteristics of Planet Nine based on theoretical models suggesting a mass between seven and seventeen times that of Earth, situated between 500 and 700 astronomical units (AU) from the Sun.
Through careful analysis, the team initially found 13 candidate pairs with separations aligning with Planet Nine’s predicted orbit. After an extensive selection process, including a detailed visual examination of the original images, they focused on one particularly promising candidate.
This leading candidate exhibited the expected properties, with angular separations ranging from 42 to 69.6 arcminutes between the IRAS and AKARI observations. Notably, there were no repeat detections at the same position over the survey periods. Further validation from AKARI data corroborated the consistency of the object’s movement, suggesting it behaves like a slow-moving body, detected only during the anticipated timeframes.
While the discovery holds promise, researchers urge caution. The data gathered from the IRAS and AKARI surveys alone may not be sufficient to solidify the claim or provide a definitive orbit for the object. The team advocates for additional observational efforts using the Dark Energy Camera (DECam), a powerful tool capable of spotting faint, moving objects in minimal exposure time.
As excitement builds around the potential identification of Planet Nine, the quest for this elusive giant continues. Scientists remain eager to explore the further mysteries of our Solar System, hoping that advanced observational techniques may soon unravel the secrets hidden in its farthest reaches.