title: The rubble-pile asteroid Itokawa as observed by Hayabusa.
abstract: During the interval from September through early December 2005, the Hayabusa spacecraft was in close proximity to near-Earth asteroid 25143 Itokawa, and a variety of data were taken on its shape, mass, and surface topography as well as its mineralogic and elemental abundances. The asteroid's orthogonal axes are 535, 294, and 209 meters, the mass is 3.51 x 10(10) kilograms, and the estimated bulk density is 1.9 +/- 0.13 grams per cubic centimeter. The correspondence between the smooth areas on the surface (Muses Sea and Sagamihara) and the gravitationally low regions suggests mass movement and an effective resurfacing process by impact jolting. Itokawa is considered to be a rubble-pile body because of its low bulk density, high porosity, boulder-rich appearance, and shape. The existence of very large boulders and pillars suggests an early collisional breakup of a preexisting parent asteroid followed by a re-agglomeration into a rubble-pile object.
authors.affiliation: Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan. fujiwara@planeta.sci.isas.jaxa.jp
authors.forename: A
authors.initials: A
authors.lastname: Fujiwara
authors.forename: J
authors.initials: J
authors.lastname: Kawaguchi
authors.forename: D K
authors.initials: DK
authors.lastname: Yeomans
authors.forename: M
authors.initials: M
authors.lastname: Abe
authors.forename: T
authors.initials: T
authors.lastname: Mukai
authors.forename: T
authors.initials: T
authors.lastname: Okada
authors.forename: J
authors.initials: J
authors.lastname: Saito
authors.forename: H
authors.initials: H
authors.lastname: Yano
authors.forename: M
authors.initials: M
authors.lastname: Yoshikawa
authors.forename: D J
authors.initials: DJ
authors.lastname: Scheeres
authors.forename: O
authors.initials: O
authors.lastname: Barnouin-Jha
authors.forename: A F
authors.initials: AF
authors.lastname: Cheng
authors.forename: H
authors.initials: H
authors.lastname: Demura
authors.forename: R W
authors.initials: RW
authors.lastname: Gaskell
authors.forename: N
authors.initials: N
authors.lastname: Hirata
authors.forename: H
authors.initials: H
authors.lastname: Ikeda
authors.forename: T
authors.initials: T
authors.lastname: Kominato
authors.forename: H
authors.initials: H
authors.lastname: Miyamoto
authors.forename: A M
authors.initials: AM
authors.lastname: Nakamura
authors.forename: R
authors.initials: R
authors.lastname: Nakamura
authors.forename: S
authors.initials: S
authors.lastname: Sasaki
authors.forename: K
authors.initials: K
authors.lastname: Uesugi