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Updated: Mar 30, 2026

Scattering And Absorption of Light in Planetary Regoliths
Published on: July 1, 2019
Boulders on asteroid Toutatis as observed by Chang'e-2
Yun Jiang1, Jianghui Ji1, Jiangchuan Huang2
1Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China.
Boulders on asteroid Toutatis suggest a highly fragmented rubble-pile structure, differing from asteroid Itokawa. Analysis indicates a surface age of approximately 1.6 billion years.
Area of Science:
- Planetary Science
- Asteroid geology
- Spacecraft remote sensing
Background:
- Boulders on small rocky bodies offer insights into geological evolution and collisional history.
- Asteroid Toutatis, a near-Earth asteroid, is a subject of interest for understanding small body formation and evolution.
Purpose of the Study:
- To analyze the spatial and size distribution of boulders on asteroid Toutatis.
- To infer the geological structure and collisional history of Toutatis.
- To estimate the surface age of Toutatis.
Main Methods:
- Utilizing images acquired by the Chang'e-2 spacecraft to identify and count boulders.
- Calculating the cumulative boulder size frequency distribution (SFD).
- Comparing Toutatis' boulder SFD with that of other asteroids, such as Itokawa.
- Analyzing the cumulative crater SFD to estimate surface age.
Main Results:
- Over 200 boulders were identified on Toutatis within the imaged area.
- The cumulative boulder SFD exhibits a steep slope (-4.4 ± 0.1), indicating significant fragmentation.
- Toutatis likely possesses a rubble-pile structure, with boulders not solely explained by impact cratering.
- Toutatis' boulder SFD slope is steeper than Itokawa's, suggesting different preservation states or formation scenarios.
- An estimated surface crater retention age of approximately 1.6 ± 0.3 billion years was determined.
Conclusions:
- The boulder distribution on Toutatis supports a rubble-pile structure and a history of high fragmentation.
- Differences in SFD slopes between Toutatis and Itokawa highlight diverse evolutionary pathways for asteroids.
- The estimated surface age provides a temporal context for Toutatis' geological processes.
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