University of Oulu

Kempf, S., Altobelli, N., Schmidt, J., Cuzzi, J. N., Estrada, P. R., & Srama, R. (2023). Micrometeoroid infall onto Saturn’s rings constrains their age to no more than a few hundred million years. Science Advances, 9(19), eadf8537.

Micrometeoroid infall onto Saturn’s rings constrains their age to no more than a few hundred million years

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Author: Kempf, Sascha1,2; Altobelli, Nicolas3; Schmidt, Jürgen4,5;
Organizations: 1Department of Physics, University of Colorado, Boulder, CO 80309, USA
2Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA
3ESA-ESAC, E-28691 Villanueva de la Cañada, Madrid, Spain
4Institut für Geologische Wissenschaften, Freie Universität Berlin, Berlin, Germany
5Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland
6Space Science Division, NASA Ames Research Center, Moffett Field, CA 94035, USA
7Institut für Raumfahrtsysteme, Universität Stuttgart, Stuttgart, Germany
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.6 MB)
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Language: English
Published: American Association for the Advancement of Science, 2023
Publish Date: 2023-08-16


There is ongoing debate as to whether Saturn’s main rings are relatively young or ancient— having been formed shortly after Saturn or during the Late Heavy Bombardment. The rings are mostly water-ice but are polluted by non-icy material with a volume fraction ranging from ∼0.1 to 2%. Continuous bombardment by micrometeoroids exogenic to the Saturnian system is a source of this non-icy material. Knowledge of the incoming mass flux of these pollutants allows estimation of the rings’ exposure time, providing a limit on their age. Here we report the final measurements by Cassini’s Cosmic Dust Analyzer of the micrometeoroid flux into the Saturnian system. Several populations are present, but the flux is dominated by low-relative velocity objects such as from the Kuiper belt. We find a mass flux between 6.9 · 10⁻¹⁷ and 2.7 · 10⁻¹⁶ kg m⁻²s⁻¹ from which we infer a ring exposure time ≲100 to 400 million years in support of recent ring formation scenarios.

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Series: Science advances
ISSN: 2375-2548
ISSN-E: 2375-2548
ISSN-L: 2375-2548
Volume: 9
Issue: 19
Article number: eadf8537
DOI: 10.1126/sciadv.adf8537
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: S.K. and J.N.C. were partially funded by NASA through the Cassini mission. J.N.C. and P.R.E. acknowledge support by the NASA Cassini Data Analysis Program (CDAP). R.S. acknowledges partial support by the DLR grant 50 OH1103. J.S. acknowledges support by the Academy of Finland.
Copyright information: © 2023 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution Non Commercial License 4.0 (CC BY-NC).