title: Boulders on asteroid Toutatis as observed by Chang'e-2.
abstract: Boulders are ubiquitously found on the surfaces of small rocky bodies in the inner solar system and their spatial and size distributions give insight into the geological evolution and collisional history of the parent bodies. Using images acquired by the Chang'e-2 spacecraft, more than 200 boulders have been identified over the imaged area of the near-Earth asteroid Toutatis. The cumulative boulder size frequency distribution (SFD) shows a steep slope of -4.4 ± 0.1, which is indicative of a high degree of fragmentation. Similar to Itokawa, Toutatis probably has a rubble-pile structure, as most boulders on its surface cannot solely be explained by impact cratering. The significantly steeper slope for Toutatis' boulder SFD compared to Itokawa may imply a different preservation state or diverse formation scenarios. In addition, the cumulative crater SFD has been used to estimate a surface crater retention age of approximately 1.6 ± 0.3 Gyr.
authors.affiliation: Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Jianghui
authors.initials: J
authors.lastname: Ji
authors.affiliation: China Academy of Space Technology, Beijing 100094, China.
authors.forename: Jiangchuan
authors.initials: J
authors.lastname: Huang
authors.affiliation: Southwest Research Institute, Boulder, Colorado 80302, USA.
authors.forename: Simone
authors.initials: S
authors.lastname: Marchi
authors.affiliation: Space Science Institute, Macau University of Science and Technology, Taipa, Macau.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Space Science Institute, Macau University of Science and Technology, Taipa, Macau.|Institute of Astronomy, National Central University, Taoyuan, Taiwan.
authors.forename: Wing-Huen
authors.initials: WH
authors.lastname: Ip