Astronomers have detected an atmosphere that shouldn't exist on an icy object beyond the orbit of Pluto — sparking calls for follow-up observations.

Japanese astronomers found evidence for a thin atmosphere surrounding the body, which is located within the Kuiper Belt in the cold outer reaches of the solar system, according to a new study published May 4 in the journal Nature Astronomy.

The object, known as (612533) 2002 XV93, is supposed to be too small and too cold to sustain an atmosphere. At about 311 miles (500 kilometers) across — a little wider than the Grand Canyon is long — the object is more than four times smaller than Pluto, which was thought to be the only body beyond Neptune with an atmosphere in our solar system.

The new observations challenge assumptions about which objects can sustain atmospheres in our solar system. However, these initial findings must be verified by outside researchers, with some experts keen to make follow-up observations with the James Webb Space Telescope (JWST) to confirm the atmosphere exists.

"This is an amazing development, but it sorely needs independent verification," Alan Stern, a planetary scientist and principal investigator for NASA's New Horizons mission to explore Pluto and the Kuiper Belt, who was not involved in the new study, told the Associated Press. "The implications are profound if verified."