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Title: Adhering grains and surface features on two Itokawa particles

We investigated the surface texture and chemical compositions of two ~40-μm particles returned from the surface regolith of asteroid Itokawa (RB-DQ04-0062 and RB-DQ04-0091) by the Japan Aerospace Exploration Agency’s Hayabusa mission. We identified splash melts, surface blistering, and many small adhering particles. Seven focused ion beam sections were extracted from both Itokawa particles, targeting one splash melt and ten adhering particles to investigate their composition and provenance and the role of micrometeoroid impacts on Itokawa’s surface. Based on the particle’s structure, mineralogy, and interface between the adhering particle and host grain, we identified lithic fragments and particles deposited by impact. These have morphologies and compositions consistent with impact-generated deposits: two have morphologies and compositions that are consistent with impact-generated silica glass, and one was a Ni-free, metallic Fe, and S-rich assemblage that was likely generated by vapor recondensation during a micrometeoroid impact. Here this study shows that, even though its regolith is young, micrometeoroid impacts have altered the regolith of asteroid Itokawa.
Authors:
 [1] ;  [2]
  1. Univ. of New Mexico, Albuquerque, NM (United States)
  2. Washington Univ., St. Louis, MO (United States)
Publication Date:
Type:
Accepted Manuscript
Journal Name:
Earth, Planets and Space (Online)
Additional Journal Information:
Journal Name: Earth, Planets and Space (Online); Journal Volume: 68; Journal Issue: 1; Journal ID: ISSN 1880-5981
Publisher:
Springer
Research Org:
Nevada Field Office, Las Vegas, NV (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Asteroid; Micrometeoroid; Regolith; Space weathering
OSTI Identifier:
1376693