Overview
- The team led by Ko Arimatsu reported the finding Monday in Nature Astronomy, describing a thin atmosphere around the Kuiper Belt object (612533) 2002 XV93, which is about 500 kilometers wide.
- They inferred the gas from a stellar occultation recorded in Japan on January 10, 2024, when the star dimmed smoothly for about 1.5 seconds instead of blinking off.
- Models match a surface pressure of roughly 100 to 200 nanobars, five to ten million times thinner than Earth’s air and far below Pluto’s tenuous atmosphere.
- The gas would vanish within hundreds to roughly a thousand years without fresh supply, with leading ideas pointing to a recent impact or ongoing cryovolcanic outgassing; JWST so far shows no surface frosts to drive steady sublimation.
- Follow-up occultations and JWST spectroscopy are planned to confirm the signal, pin down the gases, watch for pressure changes, and check alternatives such as rings or dust, which could reveal how common such atmospheres are on small distant worlds.