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Fundamentally distinct outcomes of asteroid collisional evolution: Itokawa and Eros
Author(s) -
Cheng A. F.,
BarnouinJha O.,
Hirata N.,
Miyamoto H.,
Nakamura R.,
Yano H.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl029559
Subject(s) - asteroid , regolith , astrobiology , impact crater , geology , physics
The outcomes of asteroid collisional evolution are presently unclear: are most asteroids larger than 1 km size gravitational aggregates reaccreted from fragments of a parent body that was collisionally disrupted, while much smaller asteroids are collisional shards that were never completely disrupted? The 16 km mean diameter S‐type asteroid 433 Eros, visited by the NEAR mission, has surface geology consistent with being a fractured shard. The Hayabusa spacecraft visited an S‐asteroid smaller than 1 km, namely 25143 Itokawa. Here we report the first comparative analyses of Itokawa and Eros geology. Itokawa lacks a global lineament fabric, and its blocks, craters, and regolith are inconsistent with formation and evolution as a fractured shard, unlike Eros. Itokawa is not a scaled‐down Eros, but formed by a distinct process of catastrophic disruption and reaccumulation.