A new dwarf planet, discovered beyond Neptune and described as Pluto's 'cousin,' could void the hypothesis of a Planet X in our solar system.

The object—which orbits out beyond Neptune—has been named "2017 OF201" by the team, which was led by Sihao Cheng of the Institute for Advanced Study in Princeton, New Jersey.

2017 OF201 is about one-third the size of Pluto, which was reclassified as a dwarf planet in August 2006, and "is likely large enough to qualify as a dwarf planet, and its orbit is extremely wide ...

Cheng said the discovery of 2017 OF201 has implications for hypotheses involving the potential existence of a ninth planet in our solar system, dubbed Planet X or Planet Nine.

This new dwarf planet may exist at the edge of the solar system, possibly disproving Planet Nine's existence. This is the story of that newly encountered planet.

Scientists have discovered a new dwarf planet candidate far beyond Pluto in the solar system. Its existence could mean there's no Planet 9.

Cheng said the discovery of 2017 OF201 has implications for hypotheses involving the potential existence of a ninth planet in our solar system, dubbed Planet X or Planet Nine.

Learn about the recently discovered trans-Neptunian object that may eventually join Pluto as a dwarf planet, found at the edge of our solar system.

2017 OF201 isn’t the planetary heavyweight many have been waiting for, but it’s a reminder that the solar system is still full of surprises—especially in its frigid, hard-to-see suburbs.

While further observations are required to determine its exact size, current estimates suggest that 2017 OF201 is the second-largest known object in such a wide orbit.