The third interstellar object confirmed to visit Sistema Solar revealed significant changes in its chemical composition after passing through Sol’s closest point. Observações carried out in January 2026 by Telescópio Subaru, located at Mauna Kea at Havaí, detected a considerable reduction in the proportion of carbon dioxide in relation to water in the gases released by the coma of comet 3I/ATLAS. The object, also designated C/2025 N1 (ATLAS), was discovered in July 2025 and follows a hyperbolic trajectory that keeps it gravitationally detached from Sol.
Medições post-perihelium reveals changes in gas composition
The measurements were carried out on January 7, 2026, just months after the comet reached its point of maximum solar approach in October 2025. The Telescópio Subaru, equipped with a main mirror with an effective diameter of 8.2 meters, captured detailed images of the coma using three different filters: V (550 nanometers), R (660 nanometers) and I (805 nanometers). Essa data combination allowed astronomers to analyze the proportion of gases released with unprecedented precision.
The results indicate that the ratio of CO₂ to H₂O in post-perihelion gases was significantly lower than measurements taken by space observatories before Sol’s closest pass. Essa difference points to changes in nucleus activity as the object heated up during its approach. The sublimation of surface ices exposed deeper layers of the core, releasing material with a different chemical composition than that found in the outer regions.
Estrutura in core layers explains detected variations
The observed variation in composition reflects fundamental differences between the surface and inner layers of the cometary nucleus. Materiais more volatile compounds, particularly compounds rich in carbon and oxygen, sublime at lower temperatures. As solar heating progressively removes the outer layers, the exposed interior releases gases with different ratios of carbon dioxide to water.
- Observações combined three filters allowed mapping the coma at different wavelengths.
- Análise focused on the ratio of CO₂ to H₂O in the gases released by the cometary nucleus.
- Resultados indicate layered structure in the interstellar comet nucleus.
- Mudança occurred due to progressive heating during solar approach.
- Dados will be published in the The Astronomical Journal magazine.
Essa characteristic helps to understand processes occurring in cometary nuclei of interstellar origin. Comparações with Sistema Solar comets show that objects formed in other stellar systems can have different compositions. The data contributes to the study of planet formation in young systems around other stars, offering insights into chemical diversity in different regions of the galaxy.
Visitantes interstellar confirmed in Sistema Solar
3I/ATLAS represents the third object confirmed as interstellar to cross Sistema Solar. The previous ones were 1I/’Oumuamua, detected in 2017, and 2I/Borisov, observed in 2019. Diferente of the first two, this object behaves like an active comet, releasing dust and gases when approaching Sol. The initial discovery took place on July 1, 2025 in Chile, and the velocity along the hyperbolic trajectory quickly confirmed its origin outside of Sistema Solar.
The comet passed within safe distances of planets like Marte, Vênus and Terra during its journey. The hyperbolic trajectory ensures that the object will continue its path out of Sistema Solar after this visit, moving progressively away over the next few decades. Astrônomos monitored 3I/ATLAS with several ground and space instruments over the course of months, accumulating data that reveals details about its physical and chemical evolution during its passage through perihelion.
Significado Scientific Analysis of Cometary Coma
The study of the coma allows access to information about the interior of the nucleus without the need for direct contact or exploration missions. The change in the proportion of gases reflects how solar heating affects different materials over time, offering clues about the chemical conditions in the comet’s home star system. Pesquisadores highlight that objects like 3I/ATLAS carry material formed billions of years ago, possibly in older regions of Via Láctea.
Comparison with local comets helps map differences in planetary formation processes in different regions of the galaxy. The Telescópio Subaru results contribute to models that describe the evolution of cometary nuclei under stellar influence. The work involved sophisticated combination of data from multiple filters for greater accuracy in identifying chemical components, establishing new standards for future observations of interstellar objects that visit Sistema Solar.