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<\/a><\/p>\nThese Hubble images of the fragmenting comet C\/2025 K1 (ATLAS) were taken over the course of three consecutive days: November 8, 9, and 10, 2025. Image credit: NASA \/ ESA \/ D. Bodewits, Auburn \/ J. DePasquale, STScI.<\/p>\n
\u201cSometimes the best science happens by accident,\u201d said Auburn University\u2019s Professor John Noonan, co-author of the study.<\/p>\n
\u201cThis comet got observed because our original comet was not viewable due to some new technical constraints after we won our proposal.\u201d<\/p>\n
\u201cWe had to find a new target \u2014 and right when we observed it, it happened to break apart, which is the slimmest of slim chances.\u201d<\/p>\n
C\/2025 K1 (ATLAS) reached perihelion \u2014 its closest approach to the Sun \u2014 at 0.33 AU on October 8, 2025.<\/p>\n
The event was inside Mercury\u2019s orbit, about one-third the distance of the Earth from the Sun. During perihelion, a comet experiences its most intense heating and maximum stress.<\/p>\n
Hubble images obtained on November 8-10, 2025 resolved five fragments, providing an early high-resolution view of a cometary nucleus in the process of disruption.<\/p>\n
\u201cNever before has Hubble caught a fragmenting comet this close to when it actually fell apart,\u201d Professor Noonan said.<\/p>\n
\u201cMost of the time, it\u2019s a few weeks to a month later. And in this case, we were able to see it just days after.\u201d<\/p>\n
\u201cThis is telling us something very important about the physics of what\u2019s happening at the comet\u2019s surface.\u201d<\/p>\n
\u201cWe may be seeing the timescale it takes to form a substantial dust layer that can then be ejected by the gas.\u201d<\/p>\n
C\/2025 K1 (ATLAS) is now a collection of fragments about 400 million km from Earth.<\/p>\n
Located in the constellation of Pisces, it is heading out of the Solar System, not likely to ever return.<\/p>\n
Astronomers see that long-period comets such as C\/2025 K1 (ATLAS) are more likely to fragment than their short-period cousins, such as 67P\/Churyumov-Gerasimenko that was visited by ESA\u2019s Rosetta mission, but it is not known why.<\/p>\n
Launching towards the end of the decade, ESA\u2019s Comet Interceptor will be the first mission to visit a long-period comet.<\/p>\n
\u201cHubble\u2019s chance observation of C\/2025 K1 (ATLAS) will help us understand why some long-period comets split apart and give us a first view of their interiors,\u201d said University of Edinburgh\u2019s Professor Colin Snodgrass.<\/p>\n
\u201cThese new results will complement the detailed view of a long-period comet that we will obtain from Comet Interceptor, as well as helping astronomers to select the mission\u2019s target.\u201d<\/p>\n