OF201 spends only 1% of its orbital time close enough to us to be detectable. The presence of this single object suggests ...

A potential new dwarf planet has been discovered in the outer reaches of the solar system, and its existence poses the ...

OF201 is incredibly lightweight on a cosmic scale. Scientists estimate its mass is about 20,000 times less than Earth’s and ...

A team of astronomers believe they may have discovered a new dwarf planet—just like Pluto—on the edge of our solar system.

Scientists have discovered a colossal object approximately 435 miles wide in the frigid outer reaches of our solar system, ...

Almost 20 years after Pluto was infamously downgraded from its status as a planet, scientists now believe they have ...

The unusual orbit of a possible dwarf planet, known as 2017 OF201, makes it less likely that our solar system contains a ...

The small world was found during a search for the hypothetical Planet Nine, and astronomers say the next time it will reach ...

U.S. astronomers hunting for "Planet Nine" have instead stumbled on what appears to be a new dwarf planet in the solar system's outer reaches.

A small team led by Sihao Cheng, Martin A. and Helen Chooljian Member in the Institute for Advanced Study's School of Natural ...

It's an evocative idea that has long bedeviled scientists: a huge and mysterious planet is lurking in the darkness at the ...

Given the name 2017 OF201, the object falls into a category called trans-Neptunian objects that orbit the sun at a distance ...