NASA/JPL-Caltech; Sihao Cheng et al.
The five planets dwarfs recognized by the International Astronomical Union, along with the newly discovered trans-negle object 2017 of201.
The 2017 of201 is at the limit of our solar system. It is potentially large enough to be classified as a dwarf planet.
A small team led by Sihao Cheng, from the Institute for Advanced Study (IAS), discovered an extraordinary Trans-Neptunian object (OTN) called 2017 of201, at the limit of our solar system.
OTN is potentially large enough to be classified as a dwarf planet, the same category as the much best known Pluto. The new object is one of the most distant visible objects of our solar system and, significantly, suggests that the empty section of space that is thought to exist beyond Neptune, in the waist of Kuiper, is not, in fact, empty.
Cheng did the discovery along with colleagues Jiaxuan Li and Erytas Yang at Princeton University, using Computational Methods advanced to identify the object’s trajectory in the sky. The new object was officially announced by the International Astronomical Union Center of Minor Planets on May 21, 2025, and in a scientific article still shared May 22 on the site.
Trans-neptune objects are smaller planets that orbiting the sun at an average distance higher than Neptune’s orbit. The new OTN is special for two reasons: its extreme orbit and its large size.
“The purpose of the object – the farthest point of the orbit around the sun – is more than 1600 times higher than that of the orbit of the earth“Cheng.” However, its perihelion – the point of its orbit closest to the sun – is 44.5 times higher than the Earth’s orbit, similar to Pluto’s orbit. “
This extreme orbit, which takes about 25,000 years Completing, suggests a complex history of gravitational interactions. “It must have had close meetings with a giant planetcausing it to be ejected for a wide orbit, ”says Yang.“ There may have been more than one step in your migration. It is possible that this object was first ejected to the OORT cloud, the farthest region of our solar system, where many comets are found, and then sent back, ”adds Cheng.
“Many extreme OTNS have orbits that seem to group in specific guidelines, but 2017 of201 is deviated from this,” says Li. This group has been interpreted as a indirect evidence of the existence of another planet in the solar system, planet X or planet ninethat could be gravitating these objects to their observed standards. The existence of 2017 of201 as an atypical object of such a grouping can potentially challenge This hypothesis.
Cheng and his colleagues estimate the 2017 of201 diameter by 700 km, which would make it second largest object known in such a wide orbit. The Diameter of Pluto, in turn, is 2377 km. More observations are needed, potentially using radiotelescopes to determine the exact size of the object.
Cheng discovered the object as part of an ongoing research project to identify OTNS and possible new planets in the outer solar system. The object was identified by observing brilliant points In a database of astronomical images of the Victor M. Blanco and CFHT telescope (Canada-France-Hawaii Telescope), and trying to connect all the possible groups of these points that seemed to move in the sky the same way as a single OTN. This search was done using a computationally efficient algorithm produced by Cheng. Ultimately, they identified 2017 of201 in 19 different exhibitions, captured over 7 years.
The discovery has significant implications for our understanding of the outer solar system. The area beyond the waist of Kuiper, where the object is, was previously considered to be essentially empty, But the discovery of the team suggests that Not quite.
“2017 of201 Spends only 1% of your orbital time sufficiently close to us to be detectable. The presence of this only object suggests that There may be another hundred other objects with similar orbit and size; They are just too far away To be detectable now, ”says Cheng.” Although advances in the telescopes have allowed us to explore parts far from the universe, there is still much to find out about our own solar system. “
Detection also demonstrates the power of Open Science. “All data we have used to identify and characterize this object are file data that is available to anyone, not just for professional astronomers,” Li. “This means that innovative findings are not limited to those who have access to the world’s largest telescopes. Any researcher, student or even scientist with the right tools and knowledge could have done this discovery, highlighting the value of scientific resources.”
