講演情報
[PPS03-11]Geomorphological characteristics of asteroid Ryugu: implications to its evolutional history
*宮本 英昭1、逸見 良道1、菊地 紘1、小松 吾郎2、本田 親寿3、道上 達広4、諸田 智克5、長 勇一郎1、バーノイン オリビエ6、佐々木 晶7、平田 成3、平田 直之8、本田 理恵10、亀田 真吾11、巽 瑛理1、横田 康弘12、神山 徹13、鈴木 秀彦14、山田 学15、坂谷 尚哉12、早川 雅彦12、吉岡 和夫1、松岡 萌12、平林 正稔9、澤田 弘崇12、杉田 精司1 (1.東京大学、2.ダヌンツィオ大学、3.会津大学、4.近畿大学、5.名古屋大学、6.ジョンズホプキンス大学、7.大阪大学、8.神戸大学、9.オーバーン大学、10.高知大学、11.立教大学、12.宇宙科学研究所、13.産業総合研究所、14.明治大学、15.千葉工業大学)
キーワード：
小惑星、はやぶさ２、リュウグウ
Observations by Hayabusa 2 spacecraft indicate that Ryugu is a highly porous C-type asteroid. Ryugu’s surface is covered by numerous boulders. These are consistent with the idea that Ryugu is a rubble-pile asteroid. Interestingly, Itokawa, the only other similarly-sized rubble-pile asteroid closely observed by spacecraft, is different from Ryugu in many aspects. For example, while the shape of Ryugu is a top-shape, that of Itokawa is somehow elongated cigar-like. Though Ryugu is generally homogeneous in terms of roughness, Itokawa has two distinctive areas such as smooth and rough terrains. Ryugu has an almost continuous equatorial ridge, though Itokawa does not have such a large-scale topographic feature.
These differences may come from the difference in evolutional processes; a top-shape of rubble pile asteroid is believed to result of rotationally induced deformation or from re-accumulation. Another possibility is that the differences may come from variations in mechanical properties of asteroid forming materials. We are investigating geological characteristics of Ryugu, which may hold clues for these aspects. In this talk, we report initial results of geological investigations mostly using visible images obtained by the Optical Navigation Camera (ONC) onboard the Hayabusa2 spacecraft, and discuss about their implications to evolutional history of Ryugu..
These differences may come from the difference in evolutional processes; a top-shape of rubble pile asteroid is believed to result of rotationally induced deformation or from re-accumulation. Another possibility is that the differences may come from variations in mechanical properties of asteroid forming materials. We are investigating geological characteristics of Ryugu, which may hold clues for these aspects. In this talk, we report initial results of geological investigations mostly using visible images obtained by the Optical Navigation Camera (ONC) onboard the Hayabusa2 spacecraft, and discuss about their implications to evolutional history of Ryugu..