Overview
- The Nature Astronomy paper, published Monday, says a small trans‑Neptunian world known as 2002 XV93 shows signs of a thin atmosphere based on a stellar occultation in Japan on January 10, 2024.
- Telescopes at three sites recorded the background star fading and brightening smoothly for about 1.5 seconds at the edge of the object’s shadow, a refractive signature expected when starlight passes through gas.
- Models estimate a surface pressure of roughly 100 to 200 nanobars, which is about 5 to 10 million times thinner than Earth’s air and some 50 to 100 times thinner than Pluto’s atmosphere.
- Scientists propose two leading sources for the gas, with either cryovolcanic outgassing that resupplies it or a recent impact that released volatiles, and note that JWST observations so far show no obvious surface frozen‑gas deposits.
- The result challenges assumptions that only larger bodies can retain atmospheres, yet it rests on one event, leaves room for alternatives like dust or rings, and now drives new occultation campaigns and JWST spectroscopy to confirm composition, persistence, and origin.