Overview
- Astronomers in Japan recorded 2002 XV93 passing in front of a distant star on January 10, 2024, and the star’s light dimmed smoothly for about 1.5 seconds, a sign of refraction by a thin atmosphere.
- The peer-reviewed analysis, published May 4 in Nature Astronomy, reports an atmosphere roughly 5 to 10 million times thinner than Earth’s around a body about 292 miles wide in the Kuiper Belt.
- James Webb Space Telescope data have not found surface frosts such as methane, nitrogen, or carbon monoxide, which makes steady surface sublimation an unlikely source.
- The team estimates the gas would dissipate in less than about 1,000 years without resupply and proposes cryovolcanic outgassing or a recent impact as the leading sources.
- Outside experts call for independent checks through new occultations and telescope spectra, and the authors note a close-in ring could mimic the signal but consider that scenario less likely.