Comet C/2025 K1 (ATLAS): November 2025 (annotated)

This series of Hubble Space Telescope images of the fragmenting comet C/2025 K1 (ATLAS), or K1 for short, was taken over the course of three consecutive days: November 8, 9, and 10, 2025. Captured by Hubble’s STIS (Space Telescope Imaging Spectrograph) instrument, the sequence shows the progressive disintegration of the comet over this brief period. This is the first time Hubble has witnessed a comet so early in the process of breaking up.

Hubble caught K1 fragmenting into at least four pieces, each with a distinct coma, the fuzzy envelope of gas and dust that surrounds a comet’s icy nucleus. Hubble cleanly resolved the fragments, but from the ground they only appeared as barely distinguishable blobs.

[Image description: Three annotated panels side by side show K1 fragmenting over three consecutive days. Arrows show the orientation of object on sky. From left to right, panels are labeled November 8, 2025; November 9, 2025; and November 10, 2025. Each panel shows several bright, fuzzy, blue objects streaking diagonally from upper left to lower right of black background. In first panel, four comet-like objects are numbered 1 to 4. In second panel, the largest object has broken into two pieces, 2a and 2b. In third panel, pieces appear to be moving away from each other diagonally.