Planet Nine? Not quite, but some astronomers think they've spotted a new dwarf planet

A possible new dwarf planet has been discovered at the edge of our solar system, so far-flung that it takes around 25,000 years to complete one orbit around the sun. The object, known as 2017 OF201, was found by researchers at the Institute for Advanced Study and Princeton University who were searching for “Planet Nine,” a hypothetical planet larger than Earth that is thought to orbit beyond Neptune.

A possible new dwarf planet has been discovered at the edge of our solar system, so far-flung that it takes around 25,000 years to complete one orbit around the sun.

The object, known as 2017 OF201, was found by researchers at the Institute for Advanced Study and Princeton University who were searching for “Planet Nine,” a hypothetical planet larger than Earth that is thought to orbit beyond Neptune. Some astronomers theorize that a mysterious ninth planet, which so far remains undetected, could explain an unusual clustering of objects and other anomalies observed in the outer solar system.

In searching for the elusive Planet Nine, researchers instead turned up a different resident in our cosmic backyard.

Composite image showing the five dwarf planets recognized by the International Astronomical Union, plus the newly discovered trans-Neptunian object 2017 OF201.NASA / JPL-Caltech / Sihao Cheng et al.“It’s not very different from how Pluto was discovered,” said Sihao Cheng, a member at the Institute for Advanced Study who led the research team. “This project was really an adventure.”

If confirmed, the newfound dwarf planet would be what Cheng calls an “extreme cousin” of Pluto. The findings were published on the preprint website arXiv and have not yet been peer-reviewed.