Fragmentation of Comet C/2025 K1

This series of images from NASA’s Hubble Space Telescope of the fragmenting comet C/2025 K1 (ATLAS), or K1 for short, was taken over the course of three consecutive days: Nov. 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 five 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, bright blobs.

About the colours

This image is a composite of many separate exposures made by the STIS instrument on the Hubble Space Telescope. This image was originally black and white and recorded only overall brightness. These brightness values were translated into a range of blueish hues. Such color "maps" can be useful in helping to distinguish subtly varying brightness in an image. Blue: STIS/CCD

About the data

The Hubble observations include those from program 18135 (D. Bodewits)