title: Mass and local topography measurements of Itokawa by Hayabusa.
abstract: The ranging instrument aboard the Hayabusa spacecraft measured the surface topography of asteroid 25143 Itokawa and its mass. A typical rough area is similar in roughness to debris located on the interior wall of a large crater on asteroid 433 Eros, which suggests a surface structure on Itokawa similar to crater ejecta on Eros. The mass of Itokawa was estimated as (3.58 +/- 0.18) x 10(10) kilograms, implying a bulk density of (1.95 +/- 0.14) grams per cubic centimeter for a volume of (1.84 +/- 0.09) x 10(7) cubic meters and a bulk porosity of approximately 40%, which is similar to that of angular sands, when assuming an LL (low iron chondritic) meteorite composition. Combined with surface observations, these data indicate that Itokawa is the first subkilometer-sized small asteroid showing a rubble-pile body rather than a solid monolithic asteroid.
authors.affiliation: Graduate School of Science and Technology, Kobe University, Nada, Kobe 657-8501, Japan. avell@kobe-u.ac.jp
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Abe
authors.forename: Tadashi
authors.initials: T
authors.lastname: Mukai
authors.forename: Naru
authors.initials: N
authors.lastname: Hirata
authors.forename: Olivier S
authors.initials: OS
authors.lastname: Barnouin-Jha
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Cheng
authors.forename: Hirohide
authors.initials: H
authors.lastname: Demura
authors.forename: Robert W
authors.initials: RW
authors.lastname: Gaskell
authors.forename: Tatsuaki
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Kensuke
authors.initials: K
authors.lastname: Hiraoka
authors.forename: Takayuki
authors.initials: T
authors.lastname: Honda
authors.forename: Takashi
authors.initials: T
authors.lastname: Kubota
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Matsuoka
authors.forename: Takahide
authors.initials: T
authors.lastname: Mizuno
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Nakamura
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Scheeres
authors.forename: Makoto
authors.initials: M
authors.lastname: Yoshikawa