Astronomers Report Possible Thin Atmosphere on Kuiper Belt Object 2002 XV93 During Stellar Occultation

Astronomers have detected a thin atmosphere on the trans-Neptunian object (612533) 2002 XV93, one of the smallest solar system bodies yet found with such a feature. The object, located in the Kuiper Belt, belongs to the class known as plutinos. These bodies share the same stable orbit as Pluto, completing three revolutions around the sun for every two made by Neptune.

On 10 January 2024, 2002 XV93 passed in front of a distant star, causing an occultation. Ko Arimatsu at Kyoto University and his colleagues observed the event from three locations in Japan. 5 seconds near the edge of the shadow.

“These gradual changes are best explained if the star’s light was bent by a very thin atmosphere around 2002 XV93,” says Arimatsu. The team estimates the surface pressure of this atmosphere at about 100 to 200 nanobars. That makes it roughly 5 million to 10 million times thinner than Earth’s atmosphere and about 50 to 100 times thinner than Pluto’s tenuous atmosphere.

“You could not breathe it, feel wind from it, or see anything like Earth’s sky,” says Arimatsu. ” Methane, nitrogen and carbon monoxide are the most plausible candidates for the atmosphere’s composition. The object (612533) 2002 XV93 has a diameter of less than 500 kilometres.

It was formally named after the date of its discovery nearly a quarter of a century ago. Possible causes for the atmosphere include volcanic activity, outgassing from the interior of 2002 XV93 or a cosmic collision. “This discovery challenges our conventional view of small worlds in the outer solar system,” says Arimatsu.

“Until now, clearly detectable atmospheres in the solar system were associated with planets, dwarf planets and some large satellites. ” Ben Montet at the University of New South Wales in Sydney, Australia, reacted to the findings by stating there is an atmosphere on 2002 XV93 and we don’t understand why.

“If you’re standing on the surface of this object, you’re not going to see a sky like [what] we have,” Montet said.

” @NewScientist reported that an artist’s impression shows the trans-Neptunian object (612533) 2002 XV93 blocking the light from a distant star. 1038/s41550-026-02846-1.