Miniature World Near Pluto Found to Have Atmosphere, Puzzling Scientists

Astronomers are baffled by the discovery of a thin atmosphere around 2002 XV93, a small icy body orbiting the Sun beyond Neptune. This finding positions the object as only the second Trans-Neptunian Object (TNO), following Pluto, to exhibit atmospheric characteristics, challenging long-held scientific assumptions.

“

Volatile material could be erupting from beneath the icy surface, perhaps through cryovolcano-like activity.

The atmosphere surrounding 2002 XV93 is incredibly tenuous, estimated to be five to ten million times less dense than Earth's. So thin, in fact, that it would not be perceptible as a breeze on its surface. Given its small size and weak gravity, planetary scientists believed any atmosphere would quickly dissipate into space. Projections suggest the atmosphere could vanish entirely within 100 to 1,000 years, indicating that a continuous process must be replenishing it.

Two primary theories are being considered to explain this atmospheric replenishment. The first is cryovolcanism, a phenomenon where volatile materials like water, methane, and ammonia behave like rock and magma due to extreme cold. These substances could erupt from beneath the icy surface, potentially through cryovolcanic activity, to form the atmosphere. However, this process has so far only been observed on larger celestial bodies.

“

A small icy body might have recently collided with 2002 XV93 and released gas or exposed material rich in volatile substances.

The second possibility is a recent collision. A cosmic impact could have released gases or exposed material rich in volatile substances. While such impacts are considered rare, researchers acknowledge the possibility that they might have coincidentally observed 2002 XV93 during a transient atmospheric phase caused by a recent impact. This scenario, though less probable, cannot be entirely ruled out.

“

Such impacts are likely rare, so the probability that we just happened to observe a transient atmosphere is small, but the collision scenario cannot be ruled out.

The discovery was made using the "occultation" technique, where astronomers observe a celestial body passing in front of a distant star, momentarily obscuring its light. If an atmosphere is present, its gases subtly bend the starlight, causing a gradual dimming rather than an abrupt disappearance. On January 10, 2024, three observatories in Japan successfully monitored such an event involving 2002 XV93, providing the crucial data for this surprising revelation about the distant, icy world.

“

If an object has no atmosphere, the starlight should suddenly disappear and reappear.