Telescópio Espacial Hubble recorded high-resolution images that reveal complex and unexpected activity on comet 3I/ATLAS, the third confirmed object of interstellar origin to visit our Sistema Solar. Durante a rare geometric alignment with Sol that occurred in January, the comet displayed luminous structures and jets of material that, atypically, pointed directly at the star, defying traditional models of cometary behavior.
The observations were carried out when the comet was in opposition, an orbital configuration in which it, Terra and Sol align almost perfectly, with Terra positioned in the middle. Essa privileged condition allowed Hubble’s instruments to capture with unprecedented clarity the effects of solar radiation on the object’s core, which remains too small to be resolved directly.
Analysis of the data indicates the presence of multiple symmetric jets and an asymmetrically shaped coma, providing new clues about the internal composition and processes of gas and dust release from celestial bodies formed in other stellar systems. Esses phenomena raise important questions about the dynamics and structure of interstellar visitors.
Detailed observations in January
The most revealing images were captured on January 14, 2026, showing an extensive halo around the comet’s nucleus. The Este halo showed a notable elongation in the direction of the Sol, a behavior contrary to the formation of conventional cometary tails, which are always pushed in the opposite direction by the pressure of solar radiation and the solar wind.
Using advanced image processing techniques, scientists were able to highlight even more refined structures. Foram identified jets of ejecta separated by angles of approximately 120 degrees from each other, a pattern that remained consistent throughout multiple photographic exposures taken by the telescope.
This geometric configuration of the jets suggests that the nucleus of 3I/ATLAS has a well-defined rotation. Analysis of variations in the intensity and direction of emissions allowed astronomers to estimate a rotation period of around 7.1 hours, a considerable speed for an object of this nature.
The persistence and symmetry of these patterns differ significantly from what is observed in most comets from our own Sistema Solar. The discovery opens a new window into the study of the physical mechanisms that govern activity in bodies that have spent most of their existence in distinct interstellar environments.
Visitor chemical composition
Complementary spectroscopic analyses, carried out both by Hubble and by other observatories, made it possible to determine the chemical composition of the gases that form the coma of 3I/ATLAS. The data revealed a notable predominance of carbon dioxide (CO2), which sublimates at temperatures lower than water, explaining the comet’s high activity even at a considerable distance from Sol.
In addition to carbon dioxide, smaller amounts of water vapor and carbon monoxide, common elements in comets, were detected. Essa combination of volatiles is responsible for most of the observed activity, but does not fully explain the precise and symmetrical geometry of the jets, which is likely linked to an irregular distribution of ices on the surface of the core.
Observations made by Telescópio Espacial James Webb added another piece to the puzzle, identifying traces of carbonyl sulfide, a compound that provides more clues about the chemical environment where the comet formed, outside our Sistema Solar. The object also exhibits non-gravitational acceleration, a slight deviation in its trajectory caused by the buoyancy of the ejected gases.
Interstellar trajectory and origin
The interstellar nature of 3I/ATLAS is confirmed by its hyperbolic orbit, which has an eccentricity greater than 6. A value above 1 indicates that the object is not gravitationally bound to the Sol and is just passing through our system. Após his brief visit, he will continue his journey through interstellar space, never returning.
Its speed relative to Sistema Solar, approximately 60 km/s, and its trajectory suggest that the comet originated in the thick disk of Via Láctea, a region that houses older stars. Estima It is believed that the age of 3I/ATLAS could be more than 7 billion years old, making it a relic of the early formation of planetary systems in our galaxy.
Structured standards in debate
The discovery of symmetric and Sol-directed structures generated intense debate in the astronomical community. A group of researchers argue that the observed patterns can be explained by a combination of the effects of rotation of the nucleus with an asymmetric sublimation of ices on the surface, a phenomenon already documented in some Sistema Solar comets, although rarely with such clarity and symmetry. Segundo this hypothesis, specific areas of the nucleus become active when exposed to sunlight during rotation, expelling jets of gas and dust in specific directions that, seen from Terra, create the illusion of complex structures.
On the other hand, other experts consider that the persistence and geometric regularity of the 3I/ATLAS jets are exceptional elements that may indicate physical or compositional properties different from those found in comets native to our system. The almost perfect symmetry of the jets, separated by 120 degrees, may suggest an internal structure or a distribution of material on the surface that is more organized than expected. Further investigation is considered crucial to determine whether these features are a peculiarity of 3I/ATLAS or a common feature in interstellar objects, which would have significant implications for models of comet formation elsewhere in the galaxy.
Features of the observed coma
3I/ATLAS’s coma, the cloud of gas and dust that surrounds its core, displays a particularly intriguing morphology, taking on a teardrop shape in images captured after its closest approach to Sol, known as perihelion. Essa cloud reaches a length of millions of kilometers, making the comet a vast object in space, despite its solid core being relatively small. Análises Detailed images reveal the presence of double or even triple jets emerging from the core, with a subtle oscillation that perfectly aligns with the 7.1-hour rotational period. One of the most notable phenomena is the so-called anti-tail, a dust structure that points towards Sol and which, at times, measured ten times the apparent diameter of the comet itself. Além Furthermore, spectral observations indicate a faint greenish hue in the coma, a typical signature of the emission of diatomic carbon (C2) and cyanogen (CN) molecules when excited by Sol’s ultraviolet light. Atualmente, with a magnitude of around 16.7, the comet is too faint to be seen with amateur telescopes, requiring professional equipment to monitor it.
Rare Alignment Conditions
The January 22, 2026 alignment provided ideal observing conditions, positioning the comet 3.33 Unidades Astronômicas (AU) from Sol and 2.35 AU from Terra. At Nesse moment, the phase angle – the Sol-comet-Earth angle – reached a minimum of just 0.69 degrees. Essa Favorable geometry intensified a phenomenon known as opposition surge, in which dust ejected by the comet reflects sunlight back to the observer with amplified brightness, highlighting faint structures that would otherwise be invisible.
Ongoing monitoring
Comet 3I/ATLAS will remain accessible to large ground-based and space-based telescopes until mid-2026, although its brightness will continue to progressively decrease as it moves away from Sol on its exit path from Sistema Solar. Observatórios like Gemini North, in Havaí, also contributed important data, recording the greenish hue associated with its gaseous compounds.
A coordinated research effort between different space agencies and astronomical institutions continues to analyze variations in their activity. The data collected during this rare visit is critical to deepening understanding of the formation and distribution of volatile materials in primitive bodies originating in other stellar systems, offering a valuable glimpse into the diversity of planetary building blocks in Via Láctea.
