PreprintCC BY 4.0arXiv
Partial Fragmentation of Comet C/2025 K1 (ATLAS)
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 (≲ 100 μm) dominate the coma, with average dust velocity ∼ a few × 1 meter s−1. The nucleus radius is estimated at ∼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.
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BibTeX
@misc{luu2026partial,
title = {{Partial Fragmentation of Comet C/2025 K1 (ATLAS)}},
author = {Jane Luu and David Jewitt},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.34558},
eprint = {2610.34558},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.34558},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Partial Fragmentation of Comet C/2025 K1 (ATLAS)
AU - Jane Luu
AU - David Jewitt
PY - 2026
DA - 2026/10/25
PB - arXiv
DO - 10.48550/arxiv.2610.34558
UR - https://arxiv.org/abs/2610.34558
AB - 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 (≲ 100 μm) dominate the coma, with average dust velocity ∼ a few × 1 meter s^−1. The nucleus radius is estimated at ∼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.
ER -