Astronomers using ground-based telescopes in Japan detected a thin atmosphere surrounding the small icy body
2002 XV93, located farther from the Sun than Pluto. Observations during a stellar occultation showed the star's light dimming due to atmospheric interference.
The atmosphere of 2002 XV93 is surprisingly tenuous, measured at
100 to 200 nanobars, which is
5 to 10 million times thinner than Earth's and
50 to 100 times thinner than Pluto's. Lead researcher
Ko Arimatsu emphasized that these findings challenge the standard theories of atmospheric formation, suggesting that small icy objects can indeed support atmospheres.
The atmosphere may be composed of methane, nitrogen, or carbon monoxide. Arimatsu proposed that its presence could either be supported by
ongoing cryovolcanic activity or possibly released by a recent impact with an icy body like a comet. Remarkably, this results in 2002 XV93 potentially being the first of its size to host an atmosphere, compelling astronomers to rethink earlier assumptions that only larger planets could achieve this.
Arimatsu explained,
"This discovery suggests that some small icy bodies in the outer Solar System may not be completely inactive or unchanging, as previously assumed." Future observations are critical to determine whether this atmosphere can be sustained over time.
The object orbits the Sun at an average distance of about 39.6 AU and is roughly
310 miles in diameter, requiring approximately
247 years to complete one orbit.
Sources: 
Astronomers have discovered a tenuous atmosphere around the tiny icy world 2002 XV93, located beyond Pluto. The atmosphere is believed to be 5 to 10 million times thinner than that of Earth, raising questions about traditional theories regarding planetary atmospheres, according to a study published in *Nature Astronomy*.
