Astronomers Capture Real-Time Breakup of Comet C/2025 K1 (ATLAS)
NASA's Hubble Space Telescope observed comet C/2025 K1 (ATLAS) fragmenting into multiple pieces, providing a rare opportunity to study the disintegration process of such celestial bodies.
During routine observations, NASA's Hubble Space Telescope captured the unexpected fragmentation of comet C/2025 K1 (ATLAS). The comet, discovered in May 2025 by the Asteroid Terrestrial-impact Last Alert System (ATLAS), began breaking apart as Hubble observed it from November 8 to 10, 2025.
Initially, the comet appeared intact, but subsequent data revealed it had split into at least four distinct pieces, each surrounded by its own coma. One fragment further divided during the observation period.
Comets, often described as "dirty snowballs," are composed of ice, dust, and rock. As they approach the Sun, solar heating and gravitational forces can cause them to fracture. In this instance, the breakup likely began about a week before Hubble's observations, triggered by the comet's close approach to the Sun, known as perihelion.
The timing of the fragmentation presented a unique opportunity for scientists.
Observations also indicated a delay between the breakup and the comet's brightening, suggesting that a dust layer may have formed over the fresh ice before being ejected, or that heat needed to build beneath the surface before releasing an expanding cloud of dust.
Further analysis revealed that C/2025 K1 (ATLAS) is unusually low in carbon compared to most comets, a characteristic shared by only a few other known comets.
The fragments of the comet are now drifting away from Earth, approximately 250 million miles distant, moving through the constellation Pisces and heading outward, likely never to return.
The study detailing these observations was published in the journal Icarus on February 6, 2026.