Tiny Kuiper Object Wears a Breath: Atmosphere Detected on a 500-km Plutino
Astronomers detected a surprisingly thin atmosphere around 2002 XV93, a ~500-km plutino in the Kuiper belt, via a 2024 stellar occultation observed from Japan. The inferred atmosphere is about 100–200 nanobars—extremely tenuous and likely transient—suggesting replenishment from a recent impact or ongoing cryovolcanism. This challenges the notion that atmospheres only form on large bodies and shows that small distant objects can host detectable atmospheres, with the research published in Nature Astronomy.