The nearby star Fomalhaut is orbited by a compact source, Fomalhaut b, which has previously been interpreted as either a dust-enshrouded exoplanet or a dust cloud generated by the collision of two planetesimals. Such collisions are rarely observed but their debris can appear in direct imaging. We report Hubble Space Telescope observations that show the appearance in 2023 of a second point source around Fomalhaut, resembling the appearance of Fomalhaut b twenty years earlier. We interpret this additional source as a dust cloud produced by a recent impact between two planetesimals. The positions and motion of two impact-generated dust clouds over twenty years provide constraints on the collisional dynamics in the debris belt.
Cite
@article{arxiv.2512.15861,
title = {A second planetesimal collision in the Fomalhaut system},
author = {Paul Kalas and Jason J. Wang and Maxwell A. Millar-Blanchaer and Bin B. Ren and Mark C. Wyatt and Grant M. Kennedy and Maximilian Sommer and Thomas M. Esposito and Robert J. De Rosa and Michael Fitzgerald},
journal= {arXiv preprint arXiv:2512.15861},
year = {2025}
}
Comments
Published online in Science First Release on December 18, 2025. 32 pgs, 15 figs, 6 tables. This is the author's version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution