Gemini and Apache Point Multi-band Optical Imaging Characterization of Fragmenting Long-period Comet C/2025 K1 (ATLAS)
Abstract
We present results from multi-band g, r, and i, observations of C/2025 K1 (ATLAS) taken with the Gemini North 8.1-m/GMOS imager on 2025 December 6 and December 24, and u, g, r, i, and z observations with the Astrophysical Research Consortium (ARC) 3.5-m/ARCTIC imager on 2025 December 8. We identify at least four distinct fragments in the Gemini and ARC images, designated as A, C, D, and E in these data taken between 2025 December 6 and 24. Color indices are determined from the December 8 ARC observations of fragments A and C, and from the Gemini observations on December 24 for A, C, and D. K1 has an unusually blue g-r color of ∼0.40. The color difference between the comet and its fragments at the two epochs may be explained by particle size and light-scattering effects. We used the Gemini observations to calculate dust mass-loss rates for fragments A, C, and D. We conclude that C/2025 K1 has moderate dust mass-loss rates for millimeter-sized dust of ∼50 kg/s for the A and C fragments.
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BibTeX
@misc{ingebretsen2026gemini,
title = {{Gemini and Apache Point Multi-band Optical Imaging Characterization of Fragmenting Long-period Comet C/2025 K1 (ATLAS)}},
author = {Carl Ingebretsen and Bryce T. Bolin and Meredith A. MacGregor and Carey M. Lisse and Matthew Belyakov and Gracyn Jewett and Mukremin Kilic and Marco Micheli and Davide Farnocchia and Brian Lemaux and Hyewon Suh},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.29698},
eprint = {2608.29698},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.29698},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Gemini and Apache Point Multi-band Optical Imaging Characterization of Fragmenting Long-period Comet C/2025 K1 (ATLAS)
AU - Carl Ingebretsen
AU - Bryce T. Bolin
AU - Meredith A. MacGregor
AU - Carey M. Lisse
AU - Matthew Belyakov
AU - Gracyn Jewett
AU - Mukremin Kilic
AU - Marco Micheli
AU - Davide Farnocchia
AU - Brian Lemaux
AU - Hyewon Suh
PY - 2026
DA - 2026/08/30
PB - arXiv
DO - 10.48550/arxiv.2608.29698
UR - https://arxiv.org/abs/2608.29698
AB - We present results from multi-band g, r, and i, observations of C/2025 K1 (ATLAS) taken with the Gemini North 8.1-m/GMOS imager on 2025 December 6 and December 24, and u, g, r, i, and z observations with the Astrophysical Research Consortium (ARC) 3.5-m/ARCTIC imager on 2025 December 8. We identify at least four distinct fragments in the Gemini and ARC images, designated as A, C, D, and E in these data taken between 2025 December 6 and 24. Color indices are determined from the December 8 ARC observations of fragments A and C, and from the Gemini observations on December 24 for A, C, and D. K1 has an unusually blue g-r color of ∼0.40. The color difference between the comet and its fragments at the two epochs may be explained by particle size and light-scattering effects. We used the Gemini observations to calculate dust mass-loss rates for fragments A, C, and D. We conclude that C/2025 K1 has moderate dust mass-loss rates for millimeter-sized dust of ∼50 kg/s for the A and C fragments.
ER -