3I/ATLAS: Interstellar comet 3I/ATLAS may be dotted with icy volcanoes that erupted as it neared the Sun, according to a new study. Scientists analyzing the object say that as its distance from our star decreased, multiple cryovolcanoes, volcanoes that erupt ice, gas and volatile compounds, blasted material off its surface.
The findings, posted on November 24 to the preprint server arXiv, indicate that the chemical makeup of 3I/ATLAS can account for the unusual jets of gas and dust observed. Researchers say the comet shares striking similarities with icy dwarf planets and other frozen bodies that orbit beyond Neptune, suggesting that this alien visitor behaves much like some of the outermost objects in our own solar system.
Even more remarkable, 3I/ATLAS is believed to be 7–14 billion years old, predating the birth of the Sun.
One Of Only Three Known Interstellar Visitors
The study was led by Josep Trigo-Rodríguez, a senior researcher at the Institute of Space Sciences (CSIC/IEEC), Spain. As 3I/ATLAS is only the third confirmed interstellar object, the team set out to uncover clues about its ancient origins and what it can reveal about planets and material beyond our solar system.
Using the Joan Oró Telescope at the Montsec Observatory in Catalonia and coordinating observations with other facilities the researchers collected the most detailed data yet on 3I/ATLAS.
Jets Captured Near Perihelion, Brightening Signals Intense Sublimation
On October 29, as 3I/ATLAS approached perihelion (its closest point to the Sun), astronomers noticed the comet brighten dramatically. Comets commonly glow brighter as solar heat turns their surface ice into gas, a process known as sublimation.
But in this case, the sublimation became exceptionally strong when the comet reached about 378 million kilometres from the Sun.
The Joan Oró Telescope recorded the sharpest images yet of 3I/ATLAS, revealing powerful jets of dust and gas erupting from its surface. Trigo-Rodríguez’s team believes these jets are unmistakable signatures of cryovolcanism- the release of frozen, volatile material through vents or fissures.
In our solar system, distant worlds such as Pluto and Eris are known to host cryovolcanic activity driven by internal heat. But in the case of 3I/ATLAS, researchers propose a different mechanism, the Sun’s warmth activating long-frozen gases inside the comet.
As sunlight heated the surface, carbon dioxide ice deep within the comet vaporized. The gas then forced its way through the porous, icy interior, possibly carrying along other fluids. These gases may have triggered chemical reactions with metallic grains like nickel and iron sulfides, releasing pristine, ancient material preserved since the early universe.
An Origin Lost in the Galaxy And A One-Way Journey
Scientists are still unsure where 3I/ATLAS began its journey. Some studies suggest it may have formed in the Milky Way’s thick disk, while others propose it originated in the thin disk. What is clear is that the comet is older than the solar system and has travelled through interstellar space for billions of years.
