Newly discovered dwarf planet takes 25,000 years to complete one orbit around the Sun

Astronomers have identified a distant object in the outer reaches of our solar system beyond Neptune, potentially qualifying as a new dwarf planet. This object, temporarily named 2017 OF201 was discovered from the archival data from the Blanco telescope in Chile and the Canada-France-Hawaii telescope. The discovery of this object was officially announced on 21 May 2025 by the International Astronomical Union’s Minor Planet Centre and shared in a preprint study on arXiv according to Live Science.

The diameter of 2017 OF201 is estimated to be around 700 kilometres (435 miles). This size suggests that the body is large enough for gravity to shape it into a sphere, which is one of the key criteria to be classified as a dwarf planet under the International Astronomical Union’s 2006 definition. Like Pluto, however, the orbital neighbourhood of this planet is still not clear and thus does not qualify as a full-fledged planet. It is three times smaller than Pluto but still big enough to be considered a 'dwarf planet', lead study author Sihao Chenge of New Jersey's Institute of Advanced Study said.

The object follows an extremely elongated orbit, which takes it approximately 25,000 years to complete one circuit around the Sun. At its closest point, which is also called perihelion, it is about 44.5 astronomical units (AU) from the Sun — similar to Pluto. At its farthest (aphelion), the body drifts more than 1,600 AU away, or roughly 151 billion miles. For comparison, Neptune orbits at 30 AU.

Researchers suggest 2017 OF201 has undergone a complex journey. It may have been ejected towards the distant Oort Cloud by a giant planet and then it was pulled back into the inner regions. Its orbit implies gravitational interactions with both, the giant planets and the broader galactic environment.

Due to its distance, the object is extremely difficult to detect and is visible for only 1% of its orbital path. This means there could be many more similar objects that remain unseen. Scientists estimate that up to a hundred comparable bodies may exist in the same region.

The orbit of 2017 OF201 does not align with the clustering pattern that supports the existence of the hypothetical Planet Nine. If such a planet exists, its gravitational pull might have destabilised 2017 OF201’s orbit, suggesting this new object could challenge Planet Nine models.

The discovery team, including Sihao Cheng, Jiaxuan Li, and Eritas Yang from Princeton University, continues to analyse the object. The findings have not yet been peer-reviewed, and further observation is needed to confirm its properties and understand its role in the solar system’s structure.