The spectacular breakup of comet C/2025 K1 (ATLAS), observed by the NASA/ESA Hubble Space Telescope, sheds light on the fragile nature of cometary cores and their evolution.
These Hubble images of the fragmenting comet C/2025 K1 (ATLAS) were captured from November 8 to 10, 2025. Image credit: NASA / ESA / D. Bodewits, Auburn / J. DePasquale, STScI.
“Sometimes the best science is a serendipitous discovery,” remarks study co-author John Noonan, a professor at Auburn University.
“This comet was initially observed due to new technical constraints that rendered the original target unobservable following our proposal win.”
“We had to find a new target, and just as we began observing it, it remarkably began to disintegrate. This is immensely rare.”
C/2025 K1 (ATLAS) reached perihelion—its closest approach to the Sun—on October 8, 2025, at a distance of 0.33 AU.
This event occurred inside Mercury’s orbit, about a third of the way between Earth and the Sun, where the comet faced extreme heating and stress.
Hubble’s images taken from November 8 to 10, 2025, captured five distinct pieces, offering a high-resolution glimpse of the comet’s core disintegrating.
“Never before have we observed a comet’s breakup with such precision,” Professor Noonan stated.
“Typically, we see such events weeks or even months later. This time, we captured it just days after it happened.”
“This crucial moment enhances our understanding of the physics at play on comet surfaces.”
“We may be observing the timeline required to generate a significant dust layer that can be expelled by gas.”
Currently, C/2025 K1 (ATLAS) consists of debris approximately 400 million km from Earth.
This comet, located in the constellation Pisces, is on the verge of exiting the solar system and is not expected to return.
Astronomers suggest that long-period comets like C/2025 K1 (ATLAS) are more prone to breakup compared to short-period comets such as 67P/Churyumov-Gerasimenko, which was visited by ESA’s Rosetta mission; the reasons for this remain uncertain.
ESA’s Comet Interceptor, set to launch toward the end of the decade, will mark the first mission destined to visit a long-period comet.
Professor Colin Snodgrass from the University of Edinburgh remarked, “Hubble’s fortunate observation of C/2025 K1 (ATLAS) will significantly aid our understanding of the breakup mechanisms in long-period comets, allowing us to investigate their interiors for the first time.”
“These findings will not just complement the detailed investigations of long-period comets expected from Comet Interceptor, but also assist astronomers in selecting future mission targets.”
Refer to the study published in the Journal Icarus on February 6, 2026.
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D. Bodewits et al. Continuous fragmentation after C/2025 K1 (ATLAS) passed near the Sun. Icarus, published online on February 6, 2026. doi: 10.1016/j.icarus.2026.116996
Source: www.sci.news
