Detailed observations from October 29, whose data were processed and confirmed in 2025, revealed an unexpected deviation in the orbit of comet 3I/ATLAS, the third interstellar object identified in Sistema Solar. The Este phenomenon, detected by the Atacama Large Millimeter/submillimeter Array (ALMA), indicates an acceleration beyond the gravitational influence of the The anomaly was observed during the object’s approach to perihelion, the point in its orbit closest to Sol, suggesting that intense solar radiation plays a crucial role.
An analysis conducted by engineers at NASA’s Laboratório from Propulsão to Jato (JPL) pointed to a four arcsecond deviation in the comet’s right ascension. Essa variation, equivalent to ten times the radius of Terra in a single month, demonstrates the magnitude of the non-gravitational force acting on 3I/ATLAS.
The comet, which is now moving away from Sol, remains visible to advanced telescopes, allowing continuous tracking of its altered trajectory.
Sublimation phenomenon propels cometary orbit
The unexpected acceleration of 3I/ATLAS is attributed to a natural process common in active comets, known as sublimation, which was intensified by solar proximity. Quando the comet approaches Sol, solar radiation heats the nucleus, causing the ice present on its surface to pass directly from the solid to the gaseous state, without melting. Este gas, when escaping through cracks and fissures in the nucleus, forms jets that act as small thrusters, pushing the comet and altering its orbit in a measurable way, a mechanism that has been studied in other comets in our own stellar system, but which takes on a new dimension when observed in an object of interstellar origin.
Propulsion and gas release mechanism
The gas jets emanating from comet 3I/ATLAS function as a natural propulsion system, following the third law of Newton, which establishes that for every action there is an equal and opposite reaction. As gas is expelled in one direction, the comet nucleus is propelled in the opposite direction, noticeably altering its orbital trajectory. The Este phenomenon is well documented in comets that orbit the Sol and become active as they approach the star, releasing a tail of gas and dust that makes them visible.
Sublimation, in this context, can involve different types of ice, such as water, carbon monoxide or carbon dioxide, each with different sublimation temperatures. The specific composition of the ice on 3I/ATLAS, still under investigation, may explain the intensity and nature of its observed activity.
Unusual brightness and composition of 3I/ATLAS
Comet 3I/ATLAS exhibited a brighter increase than expected, presenting a dominant blue hue that caught the attention of astronomers. Este unusual brightness suggests a particular composition and a fast-paced release of volatile material.
A recent study, whose results were validated in 2025, attributes this variation in brightness to the emission of specific gases, indicating that the comet demonstrates a high and sustained level of activity.
Elevated activity in interstellar comets
3I/ATLAS activated its sublimation mechanisms intensely as it approached Sol, resulting in the continuous release of mass from its core. The observed emission rate is remarkable, especially for an object of interstellar origin.
Comets from other stellar systems rarely exhibit such intensity of activity, which makes 3I/ATLAS a unique and valuable object of study for understanding planetary formation outside our system. Its volatility offers clues about the conditions of its home system.
Lost mass and volatility calculations
Researchers calculated the mass loss necessary to justify the acceleration observed in 3I/ATLAS. Estimates indicate that a significant fraction of the core’s total mass, at least one-sixth, may have dissipated due to sublimation. Essa substantial loss is compatible with the nature of a highly volatile comet, rich in compounds that sublime easily under solar radiation.
Continued observations are crucial in the coming weeks and months, with specialized telescopes monitoring the comet’s trajectory and behavior in real time to refine these calculations.
Continuous observations and model refinement
Additional data collected by ALMA is expected to refine the 3I/ATLAS orbital model, allowing for a more accurate prediction of its future trajectory. Astrônomos closely monitor the variations in brightness and the morphology of the comet’s tail.
The detailed analysis of the data seeks to exclude any other influence other than non-gravitational acceleration resulting from sublimation.
Monitoring the trajectory and future of the object
Comet 3I/ATLAS will return to interstellar space gradually, but its scientific legacy will endure. Ongoing analyzes will continue to provide important information about its composition.
