Astronomers Detect Thin Atmosphere Around Small Kuiper Belt Object

Tue, 05 May 2026 08:05:00 +0200

Astronomers in Japan have detected a thin atmosphere surrounding a small trans-Neptunian object (TNO) in the Kuiper Belt, challenging previous assumptions that only larger bodies like Pluto could support atmospheres. The object, designated (612533) 2002 XV93, measures approximately 311 miles (500 kilometers) in diameter, far smaller than Pluto’s 1,477 miles (2,377 kilometers). Observations were made during a rare stellar occultation event in January 2024, when 2002 XV93 passed in front of a bright star, allowing scientists to measure subtle changes in starlight. The gradual dimming of the star suggested the presence of an atmosphere, estimated to be 5 to 10 million times thinner than Earth’s. Researchers propose two possible origins: outgassing from cryovolcanoes or a recent impact by another Kuiper Belt object releasing trapped gases. Future studies using stellar occultation or the James Webb Space Telescope could reveal the atmosphere’s composition, such as methane or carbon monoxide