The International Astronomical Union has officially added 2017 OF201 to its catalog of minor planets. Though technically a trans-Neptunian object, it’s likely to be reclassified as a dwarf planet soon. And it’s not just any frozen rock—it’s one of the most remote and enigmatic objects ever detected in our solar system.
Meet the newcomer. 2017 OF201 orbits far beyond Neptune, deep in the solar system’s outermost frontier. Although the object was first detected in 2011, it took 19 exposures collected over seven years for scientists to analyze and confirm its orbit and nature.
What makes 2017 OF201 extraordinary is both its size and its astonishingly long orbital period. It takes roughly 25,000 years to complete a single trip around the Sun.
A giant on the fringes. Despite its distance, this object is no cosmic pebble. At its closest approach to the Sun—its perihelion—2017 OF201 comes within 44.9 astronomical units (AU), roughly in the same range as Pluto. But at its farthest point, or aphelion, it reaches an incredible 1,600 AU. For comparison, Neptune orbits at about 30 AU.
Astronomer Sihao Cheng and colleagues at the Institute for Advanced Study estimate the object’s diameter at around 435 miles, making it potentially the second-largest known object in such a wide and elongated orbit—just behind Ceres, which measures about 1530 miles across.
A hint of hidden worlds. The discovery of 2017 OF201 is more than a cosmic curiosity. It suggests that the region beyond the Kuiper Belt may be far more crowded than previously believed. Currently, the object is about 90.5 AU from the Sun and is only detectable during about 0.5% of its orbital period—when it’s near perihelion.
This implies that hundreds of similar objects could exist, most of them currently undetectable. Cheng’s team estimates that these hidden worlds could collectively amount to about 1% of Earth’s mass—a significant figure that could reshape theories about the outer solar system’s structure.
Planet Nine: still in play? The orbit of 2017 OF201 may also challenge existing models about the elusive Planet Nine—a hypothetical planet theorized to explain the orbits of distant trans-Neptunian objects. This discovery adds new data that could support, refine, and even refute Planet Nine hypotheses.
Waiting for a name. Now formally recognized, 2017 OF201 has yet to receive an official name. But its significance is already clear: It offers new insights into how our solar system formed and how its outer regions behave.
The object was discovered using open-access data from the Dark Energy Camera Legacy Survey, based at the Víctor M. Blanco Telescope, and the Canada-France-Hawaii Telescope—a reminder of the value of publicly available astronomical data.
Image | Javier Miranda (Unsplash)
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