The JANUS scientific imager, integrated into the European Space Agency’s Jupiter Icy Moons Explorer (Juice) mission, has procured novel imagery of the interstellar entity designated 3I/ATLAS.
This depiction of the interstellar visitor 3I/ATLAS was acquired by the JANUS optical instrument aboard ESA’s Juice spacecraft on November 6, 2025, a mere seven days subsequent to the comet’s closest orbital trajectory to the Sun. At that juncture, Juice maintained a separation of approximately 66 million kilometers (41 million miles) from the celestial body. The supplementary panel within the visual data presents the identical dataset, albeit subjected to processing that accentuates the structural characteristics of the comet’s coma. The directional indicators situated in the upper left quadrant denote the trajectory of the comet’s motion (rendered in blue) and the relative orientation of the Sun (represented by yellow). Credit for the image: ESA / Juice / JANUS.
The entity 3I/ATLAS was initially detected on July 1, 2025, by the ATLAS survey telescope, a project supported by NASA, located in Rio Hurtado, Chile.
This cometary body, originating from beyond our solar system, also identified by the designations C/2025 N1 (ATLAS) and A11pl3Z, appears to have traversed into our Solar System originating from the celestial expanse of the constellation Sagittarius.
The trajectory of this object exemplifies the most dynamically extreme orbit ever systematically measured within the confines of the Solar System, thereby reinforcing its extragalactic provenance and its exceptional velocity.
On October 30, 2025, 3I/ATLAS achieved its perihelion, the point in its orbit closest to our Sun.
It approached within 1.4 AU (equivalent to 210 million kilometers, or 130.5 million miles) of our home star, situating it just inside the orbital path of Mars.
Throughout the duration of November 2025, the Juice spacecraft leveraged five of its specialized scientific instruments – namely JANUS, MAJIS, SWI, PEP, and UVS – to conduct observations of 3I/ATLAS.
Collectively, these instruments amassed data intended to elucidate the comet’s behavior and its constituent materials.
“During the sequential months following the observational period, Juice was positioned on the opposing solar hemisphere relative to Earth,” stated members of the Juice mission team.
“The spacecraft was strategically employing its primary high-gain antenna to function as a thermal shield, while its secondary, smaller medium-gain antenna was utilized for transmitting data back to Earth at a diminished transmission rate.”
“Consequently, it was necessary to defer receiving the collected data until the preceding week,” they elaborated.
“Our team is presently engaged in intensive efforts to meticulously analyze this information.”
In its entirety, the JANUS camera captured upwards of 120 distinct images of 3I/ATLAS, spanning a broad spectrum of wavelengths.
The scientific community is undertaking a detailed examination of all these captured images to ascertain the revelations they offer regarding the cometary body.
Furthermore, investigations into spectrometry data are ongoing, alongside the analysis of compositional data pertaining to the comet and its particulate matter.
“[The recently disseminated JANUS image] clearly exhibits energetic outflows originating from the nucleus of 3I/ATLAS, directed away from the Sun,” remarked Professor Avi Loeb of Harvard University.
“This observation presents a surprising phenomenon, considering that localized accumulations of ice on a rocky surface are anticipated to be heated by solar radiation on the side facing the Sun, thereby generating outflows initially directed towards the Sun.”
“This visual evidence bears a striking resemblance to imagery captured by amateur astronomers from Earth during the contemporaneous period.”
