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Appears in Collections:Biological and Environmental Sciences Journal Articles
Peer Review Status: Refereed
Title: Boulder sizes and shapes on asteroids: A comparative study of Eros, Itokawa and Ryugu
Author(s): Michikami, Tatsuhiro
Hagermann, Axel
Keywords: Asteroids
Asteroid Eros
Asteroid Itokawa
Asteroid Ryugu
Issue Date: 15-Mar-2021
Date Deposited: 4-Mar-2021
Citation: Michikami T & Hagermann A (2021) Boulder sizes and shapes on asteroids: A comparative study of Eros, Itokawa and Ryugu. Icarus, 357, Art. No.: 114282.
Abstract: In order to understand the geological evolution of asteroids Eros, Itokawa and Ryugu and their collisional history, previous studies investigated boulder size distributions on their surfaces. However, quantitative comparison of these size distributions is hampered by numerous differences between these studies regarding the definition of a boulder's size, measuring technique and the fitting method to determine the power-index of the boulder size distributions. We provide a consistent and coherent model of boulder size distributions by remeasuring the boulders on the entire surfaces of Eros and Itokawa using the Small Body Mapping Tool (SBMT) and combining our observations with the Ryugu data of Michikami et al. (2019). We derived power-indices of the boulder size distributions of −3.25 ± 0.14 for Eros, −3.05 ± 0.14 for Itokawa and −2.65 ± 0.05 for Ryugu. The asteroid with the highest number density of boulders ≥ 5 m turns out to be Ryugu, not Itokawa, as suggested by an earlier study. We show that the appearance of the boulders tends towards more elongated shapes as the size of an asteroid decreases, which can be explained by differences in asteroid gravity and boulder friction angles. Our quantitative observational results indicate that boulder migration preferentially affects smaller boulders, and tends to occur on larger asteroids.
DOI Link: 10.1016/j.icarus.2020.114282
Rights: This article is available under the Creative Commons CC-BY-NC-ND license ( and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed. For commercial reuse, permission must be requested.
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