New tiny ice world discovered with an atmosphere beyond Neptune dubbed a 'Mini-Pluto'

A new tiny ice world has been discovered beyond Pluto surrounded by a thin atmosphere, scientists revealed.

The "mini-pluto" is thought to be the solar system's smallest object, but still has a clearly detected global atmosphere bound by gravity, researchers said.

It was found passed the outermost planet of Neptune and "changes our view of small worlds in the solar system", according to scientists.

Previously, the dwarf planet of Pluto was the only celestial body beyond Neptune that was known to have an atmosphere.

But now an atmosphere has been observed on another body, a cosmic ice ball formally known as (612533) 2002 XV93 and with a diameter of roughly 310 miles (500km).

That makes it much smaller than Pluto, which has a diameter of 1,473 miles (2,370 km).

The so-called minor planet's atmosphere is between five and 10 million times thinner than Earth's, according to a study published on Monday in the journal Nature Astronomy, and its origins are yet to be determined.

The researchers said this object's atmosphere may be dominated by methane, nitrogen or carbon monoxide.

"The discovery suggests that some small ​icy bodies in the outer solar system may not be completely inactive or unchanging, as previously assumed," said astronomer Ko Arimatsu, head of the Ishigakijima Astronomical Observatory, a lecturer at the ​National Astronomical Observatory of Japan and lead author of the study.

"It was generally thought that an atmosphere would not exist on such a small object," said astronomer and study co-author Junichi Watanabe, director of the Koyama Space Science Institute at Kyoto Sangyo University and a professor at the National Astronomical Observatory of Japan.

"This suggests that even in a distant, cold world, there ​are dynamisms we haven't imagined."

Professor Ko Arimatsu added: "It changes our view of small worlds in the solar system, not only beyond Neptune," adding that finding an atmosphere around such a small object was "genuinely surprising."

He added that it challenges "the conventional view that atmospheres are limited to large planets, dwarf planets and some large moons."

There are two possible explanations for this, including that it may be an enduring atmosphere, perhaps sustained by cryovolcanism - a form of cold volcanism that occurs on icy moons - with gases seeping or ​venting from its interior through cracks on its surface, researchers said.

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"This would not be a volcano like on Earth, with molten rock, but a cold icy-world version involving volatile gases and ices," Prof Arimatsu said.

Alternatively, the ‌atmosphere could ⁠be temporary, caused by gases released when another smaller object struck this one relatively recently.

"If the atmosphere was impact-generated, it may decline over the next several years or decades. If it persists or varies seasonally, that would favour ongoing internal supply," Prof Arimatsu added.

(c) Sky News 2026: New tiny ice world discovered with an atmosphere beyond Neptune dubbed a 'Mini-Pluto'