Astrônomos detected a thin atmosphere around a small icy object orbiting Sol beyond Netuno’s orbit. The celestial body, called (612533) 2002 XV93, has around 250 kilometers in radius and is located in the Kuiper belt, almost 6 billion kilometers from Terra. The discovery was published this Monday (4) in the journal “Nature Astronomy” and challenges established conceptions about which celestial bodies can maintain stable atmospheres.
Até At the moment, only Plutão had a confirmed atmosphere among trans-Neptunian objects. Tentativas’s previous attempts to detect atmospheres on larger dwarf planets, such as Eris, Makemake, and Quaoar, have not yielded similar results.
Observação by stellar occultation allowed the identification
The team led by astronomer Ko Arimatsu of Observatório Astronômico Nacional of Japão used a precise method called stellar occultation. Nessa technique, the object passes in front of a star seen from Terra and temporarily blocks its light. Analyzing how this brightness decreases over time allows us to identify characteristics of the celestial body, including size, shape and the presence of material around it. Esse method proved decisive in confirming the existence of the atmosphere.
The observation took place on January 10, 2024 from three strategic points of Japão:
- A compact telescope installed on the terrace of Universidade of Kyoto
- A 1.05 meter Schmidt telescope at the Kiso observatory, equipped with a high temporal resolution camera
- A 25-centimeter telescope operated by amateur astronomer Katsumasa Hosoi at Fukushima
Padrão gradual light revealed the presence of gas
Objetos without atmosphere exhibit a characteristic pattern: the star’s light disappears abruptly when occulted. The (612533) 2002 XV93 behaved completely differently. The light gradually dimmed throughout the occultation, a signature that indicates the presence of a thin layer of gas around the object. Esse gas slightly bends the light rays before full blocking, producing the observed effect.
The data collected revealed an atmospheric pressure between 100 and 200 nanobars. Para to put it into context, this measurement represents about 5 to 10 million times thinner than the Earth’s atmosphere. Apesar of extreme lightness, the confirmation of this gaseous layer marks a significant advance in understanding the formation and persistence of atmospheres on small bodies in space.
Composição chemistry remains open
Pesquisadores tested three possible scenarios for the chemical composition of the detected gas: methane, nitrogen or carbon monoxide. The three models appear to be compatible with the observational data collected, preventing, for now, the definitive identification of the true composition. Esses compounds are precisely the same as those that form Plutão’s atmosphere, suggesting a common chemical origin among the trans-Neptunian objects.
The impossibility of distinguishing which gas dominates the atmosphere does not diminish the scientific value of the discovery. Ela opens new avenues for subsequent studies using more advanced equipment or alternative observational methods.
Implicações for understanding trans-Neptunian bodies
The existence of an atmosphere on such a small and distant object reshapes previous theoretical models. Cientistas believed that only bodies of considerable size would be able to retain gases against the pressure of solar radiation and solar wind. The (612533) 2002 XV93 demonstrates that this rule has exceptions. Seu relative size and distance from Sol create unique conditions for maintaining a thin gaseous envelope.
Estudos futures over other objects in the Kuiper belt may reveal whether this atmosphere represents an isolated case or a more common phenomenon. The stellar occultation methodology, validated in this discovery, offers a viable avenue for large-scale investigations in these extreme regions of Sistema Solar.