New planet found beyond Neptune — could it be planet nine of our Solar System?

New dwarf planet discovery challenges old ideas about Planet Nine (Image: AI generated)

Not everything hidden in deep space needs to be massive. Sometimes, it’s a quiet, distant wanderer that sparks the biggest questions. Astronomers have recently spotted one such object — a newly confirmed dwarf planet, named 2017 OF201, drifting far beyond Neptune’s orbit.

The object is about 700 kilometres wide and lies nearly three times farther from Earth than Neptune. Its highly elongated orbit takes it more than 1,600 times farther from the Sun than Earth, pushing it deep into the Oort cloud — the icy shell at the edge of the solar system.

The find came from a US research team searching for the elusive Planet Nine. While their main target remained out of reach, they stumbled upon this new body instead. The lead researcher, Sihao Cheng from the Institute for Advanced Study in New Jersey, said the dwarf planet takes nearly 25,000 years to complete a full orbit around the Sun.

Because of its long journey, OF201 is only visible for a tiny fraction of that time. “It’s already getting fainter and fainter,” Cheng shared. That’s because the object is now slipping back into darkness after its brief appearance.

Despite being much smaller than Pluto, scientists believe the object is large enough to qualify as a dwarf planet. Pluto itself lost its planet status in 2006 and was reclassified as a dwarf.

Sam Deen, a 23-year-old amateur astronomer, also tracked the object independently. He discovered traces of it in archived data. “OF201 is, in my opinion, one of the most interesting discoveries in the outer solar system in the last decade,” he said.

The idea of Planet Nine came from noticing that icy objects in the Kuiper Belt tend to cluster in a specific way. Some scientists suggested a hidden planet’s gravity might be behind this pattern. Planet Nine, they believed, could be up to 10 times the size of Earth.

But 2017 OF201 breaks this pattern. It doesn’t follow the same clustered path, casting doubt on the earlier theory. Cheng admitted this creates a challenge. “It could pose a problem for the Planet Nine theory,” he said. Still, he stressed that more data is needed before making final conclusions.

Astronomer Samantha Lawler from the University of Regina in Canada called it a “great discovery.” She also noted it weakens the main argument for Planet Nine. “The original argument for Planet Nine is getting weaker and weaker,” she said.

Cheng believes there's still more to uncover in our own solar system. “Big telescopes can now see almost to the edge of the universe,” he said. “But what is in our backyard still largely remains unknown.”

His team is now seeking time with major observatories like the James Webb Space Telescope and the Hubble. They hope to study the object in more detail.

At the same time, astronomers are excited about the upcoming Vera Rubin Observatory in Chile. The facility is expected to become operational later this year. Deen remains hopeful. “With Vera Rubin on the horizon,” he said, “I don’t think we’ll have to wonder about its existence for much longer.”