Agência Espacial Europeia (ESA) shared new visual analyzes of the interstellar comet 3I/ATLAS, based on captures made by the Juice probe during its trajectory towards the Jovian system. The images were obtained by the JANUS scientific instrument in November 2025, when the spacecraft was approximately 66 million kilometers from the object. The records detail the activity of the celestial body shortly after its passage through perihelion, revealing striking characteristics of its physical structure and dynamic behavior in space.
The comet, which crossed the inner Sistema Solar in the second half of 2025, showed intense sublimation activity due to its proximity to solar heat. Esse process resulted in the formation of a bright coma and a visible tail, elements that were meticulously documented by the European mission. The object’s closest approach to Terra occurred in December of the same year, at a safe distance of 270 million kilometers, allowing several observations to be carried out without risk of collision.
Details of the structure and surface activity
Photographs captured by the JANUS camera provide a clear view of the morphology of 3I/ATLAS. The coma is presented as a luminous spherical cloud that surrounds the nucleus, while the tail projects in the opposite direction to Sol, directly influenced by the pressure of solar radiation. Além of these main structures, scientists identified jets of material being expelled from the nucleus, which indicates the presence of active zones on the comet’s surface. The images also contain technical markings that help understand the direction of movement and relative position of the Sol.
The optical instrument recorded more than a hundred images during the encounter, complementing data from other onboard sensors such as the MAJIS spectrometer and the PEP particle detector. The processing of this information was carried out after transmitting the data to Terra, a task that required the use of the probe’s medium gain antenna, as the main antenna was positioned to act as thermal protection during that phase of the mission.
Chemical composition and interstellar origin
Spectroscopic analyzes revealed peculiarities in the chemical composition of 3I/ATLAS that differentiate it from comets formed in our own planetary system. Estudos point to an unusual abundance of nickel and a low proportion of iron, suggesting that the object formed under different conditions. Além Furthermore, the detection of a high ratio of carbon dioxide to water in the coma reinforces the theory that the celestial body originated in an extremely cold and distant region, possibly in another stellar system, before being ejected into interstellar space.
Combining optical images with ultraviolet and submillimeter wave measurements allowed researchers to map the distribution of volatiles around the nucleus. Essa integration of data from multiple instruments provides a more complete perspective on the comet’s evolution and its physical properties. Comparing this information with records from other space missions is essential to identify unique patterns and validate theoretical models about the formation of interstellar objects.
Future trajectory and scientific legacy
Currently, comet 3I/ATLAS continues its return journey to interstellar space, progressively moving away from Sol and decreasing its sublimation activity. Embora the object is leaving the vicinity of Terra, the data set collected by the Juice probe remains a valuable resource for the astronomical community. Continued analysis of this information promises to refine understanding of the chemical and structural diversity of smaller bodies roaming the galaxy.
Communication challenges faced due to the distance and orientation of the probe during capture did not impede the success of the observation. ESA teams continue to work on decoding the signals to extract additional details about the core’s internal structure. Studying this interstellar visitor represents a rare opportunity to examine materials from outside Sistema Solar, contributing significantly to the advancement of planetary science.