CAPE CANAVERAL, Fla. (AP) – A recent study has revealed that a small, icy celestial body located beyond Pluto hosts a fragile atmosphere, potentially resulting from volcanic activity or a comet impact. This dwarf planet, measuring roughly 300 miles (500 kilometers) across, is currently regarded as the smallest known object in the solar system with a detectable global atmosphere maintained by gravitational forces.
Ko Arimatsu, the lead researcher from the National Astronomical Observatory of Japan, expressed significant excitement about this finding, although he emphasized the necessity for independent verification. Alan Stern, a prominent scientist at the Southwest Research Institute and the principal investigator of NASA's New Horizons mission to Pluto, echoed this sentiment, stating that the implications of such a discovery are profound, should it be confirmed.
The study, which contributes valuable knowledge regarding the solar system's most distant and coldest objects, was conducted in a region known as the Kuiper Belt. Observations were made using three telescopes in Japan in January 2024, during an event where the icy body, designated as (612533) 2002 XV93, passed in front of a background star, leading to a temporary dimming of the starlight.
Arimatsu pointed out that the discovery alters our understanding of smaller celestial bodies within the solar system, particularly those located beyond Neptune. The presence of an atmosphere surrounding such a compact object is not only surprising but also challenges the prevailing belief that atmospheres are exclusive to larger planets, dwarf planets, and significant moons.
The object in question, classified as a plutino, orbits the sun twice for every three orbits completed by Neptune. At the time of observation, it was situated more than 3.4 billion miles (5.5 billion kilometers) from Earth, placing it in a region farther than Pluto—currently the only other Kuiper Belt object confirmed to have an atmosphere.
The atmosphere surrounding this mini Pluto is estimated to be between 5 million to 10 million times less dense than Earth's atmosphere. Furthermore, it is reported to be 50 to 100 times thinner than Pluto's own atmosphere. The most likely components of the atmosphere include methane, nitrogen, or carbon monoxide, which could account for the observed starlight dimming during the stellar occultation.
Future observations, particularly those conducted with NASA's Webb Space Telescope, are essential for confirming the atmospheric composition. Arimatsu stressed the importance of continued monitoring, stating that if the atmosphere diminishes in the coming years, it may suggest an origin linked to impacts. On the other hand, if the atmosphere remains consistent or exhibits seasonal changes, it could indicate an ongoing supply of gases generated from internal sources, such as ice volcanoes.
In conclusion, this discovery marks a significant step in our understanding of celestial objects in the Kuiper Belt and highlights the complexities of smaller bodies within our solar system. The ongoing research will be critical for shedding light on the origins and nature of this intriguing atmospheric presence.
