The Brittle Boulders Of Dwarf Planet Ceres

Spatial boulder distribution for several craters for which an age estimate is available. Green, small dots represent boulders with a size between 3 and 4 pixels (105 m < d < 140 m). Red, large dots represent boulders larger than 4 pixels (d > 140 m). The FC2 image number is indicated in the top right.

We mapped all boulders larger than 105 m on the surface of dwarf planet Ceres using images of the Dawn framing camera acquired in the Low Altitude Mapping Orbit (LAMO).

We find that boulders on Ceres are more numerous towards high latitudes and have a maximum lifetime of 150±50 Ma, based on crater counts. These characteristics are distinctly different from those of boulders on asteroid (4) Vesta, an earlier target of Dawn, which implies that Ceres boulders are mechanically weaker. Clues to their properties can be found in the composition of Ceres' complex crust, which is rich in phyllosilicates and salts. As water ice is though to be present only meters below the surface, we suggest that boulders also harbor ice.

Furthermore, the boulder size-frequency distribution is best fit by a Weibull distribution rather than the customary power law, just like for Vesta boulders. This finding is robust in light of possible types of size measurement error.

Stefan Schröder, Uri Carsenty, Ernst Hauber, Carol Raymond, Christopher Russell

Comments: Accepted by the Planetary Science Journal, 31 pages, 14 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2105.11841 [astro-ph.EP] (or arXiv:2105.11841v1 [astro-ph.EP] for this version)
Submission history
From: Stefan Schröder
[v1] Tue, 25 May 2021 11:23:41 UTC (4,712 KB)
https://arxiv.org/abs/2105.11841

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