Year: 2026
Type: preprint
Abstract: We present time-series observations of the long period comet C/2025 K1 (ATLAS) obtained in 2025-2026, bracketing the comet's fragmentation in early November 2025. We show that a simple radiation pressure model can explain many of the comet's properties: the rapid fading after fragmentation, the increasing mean particle size in the projected photometry aperture, and the time dependence of the surface brightness profile. Small dust particles ($\lesssim 100 μ$m) dominate the coma, with average dust velocity $\sim$ a few $\times$ 1 meter s$^{-1}$. The nucleus radius is estimated at $\sim$0.5 km and the dust properties are consistent with, but do not prove, an origin in nucleus rotational breakup, followed by being swept down the tail by radiation pressure.
Source: arXiv (Cornell University)
Authors: Luu, Jane, Jewitt, David
Institutions: University of Oslo, University of California, Los Angeles
Language: English
Topic: Astro and Planetary Science
Subfield: Space and Planetary Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
Funder: Norges Forskningsråd
Award: G5347054876
OpenAlex ID: W7223963796