Potential discovery of new dwarf planet adds wrinkle to Planet Nine theory

New York Post

31-05-2025

A team of scientists at the Institute for Advanced Study School of Natural Sciences in Princeton, New Jersey, might have found a new dwarf planet, potentially leading to more evidence of a theoretical super-planet.
The scientists announced in a news release that they have found a trans-Neptune Object(TNO), code-named 2017OF201, located past the icy and desolate region of the Kuplier Belt.
The TNO, which are described as minor planets that orbit the sun at a greater distance than Neptune, were found on the edge of our solar system.
While there are plenty of other TNOs in the solar system, what makes 2017OF201 special is its large size and extreme orbit.
One of the team leads, Sihao Cheng, along with Jiaxuan Li and Eritas Yang from Princeton University, made the discovery.
The team used advanced computational methods to identify the object's distinctive trajectory pattern in the sky.
'The object's aphelion — the farthest point on the orbit from the Sun — is more than 1600 times that of the Earth's orbit,' Cheng said in the release. 'Meanwhile, its perihelion — the closest point on its orbit to the Sun — is 44.5 times that of the Earth's orbit, similar to Pluto's orbit.'
5 While there are plenty of other TNOs in the solar system, what makes 2017OF201 special is its large size and extreme orbit.
Sihao Cheng et al.
5 The orbits of several TNO's including 2017OF201 labeled 'This TNO.'
Sihao Cheng et al.
2017OF201 takes about 25,000 years to orbit the sun, making Yang suggest that 'It must have experienced close encounters with a giant planet, causing it to be ejected to a wide orbit.'
Cheng also added that there may have been more than one step in its migration.
'It's possible that this object was first ejected to the Oort cloud, the most distant region in our solar system, which is home to many comets, and then sent back,' Cheng said.
This discovery has significant implications for the current understanding of the layout of our outer solar system.
5 2017OF201 takes about 25,000 years to orbit the sun.
Sihao Cheng et al.
According to NASA, California Institute of Technology (Caltech) astronomers Konstantin Batygin and Mike Brown in January 2016 announced research that provided evidence for a planet about 1.5 times the size of Earth in the outer solar system.
However, the existence of Planet X or Planet Nine is strictly theoretical as neither astronomer has actually observed such a planet.
The theory puts the planet at around the same size as Neptune, far past Pluto somewhere near the Kuiper Belt, where 2017OF201 was located.
5 The four planets and sun of our solar system.
NASA
If it exists, it is theorized to have a mass of up to 10 times as much as Earth's with a distance of up to 30 times further than Neptune to the Sun.
It would take between 10,000 and 20,000 Earth years to make one full orbit around the Sun.
However, the area beyond the Kuiper Belt, where the object is located, had previously been thought to be essentially empty, but the team's discovery suggests that this is not so.
5 An artistic concept of the theorized Planet Nine made by Caltech on Jan. 20, 2016.
Caltech/AFP via Getty Images
Cheng said in the release that 2017OF201 only has about 1% of its orbit visible to us.
'Even though advances in telescopes have enabled us to explore distant parts of the universe, there is still a great deal to discover about our own solar system,' Cheng said.
NASA mentioned that if Planet Nine exists, it could help explain the unique orbits of some smaller objects in the distant Kuiper Belt.
As of now, Planet Nine remains all but a theory, but the existence of this far-off world rests on gravitational patterns in the outer solar system.