Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu-A spinning top-shaped rubble pile.
Sei'ichiro WatanabeMasatoshi HirabayashiNaru HirataNaoyuki HirataRina NoguchiYuri ShimakiH IkedaEri TatsumiMakoto YoshikawaS KikuchiHikaru YabutaTomoki NakamuraShogo TachibanaYoshiaki IshiharaTomokatsu MorotaKohei KitazatoNaoya SakataniKoji MatsumotoKoji WadaHiroki SenshuChikatoshi HondaTatsuhiro MichikamiHiroshi TakeuchiToru KouyamaRie HondaShingo KamedaT FuseH MiyamotoGoro KomatsuSeiji SugitaTatsuaki OkadaNoriyuki NamikiMasahiko ArakawaMasateru IshiguroMasanao AbeR W GaskellEric E PalmerOlivier S BarnouinPatrick MichelA S FrenchJ W McMahonDaniel J ScheeresP A AbellYukio YamamotoS TanakaKei ShiraiMoe MatsuokaManabu YamadaYasuhiro YokotaHidehiko SuzukiKazuo YoshiokaYuichiro ChoS TanakaN NishikawaT SugiyamaH KikuchiR HemmiT YamaguchiNaoko OgawaGo OnoYuya MimasuKento YoshikawaT TakahashiYuto TakeiAtsushi FujiiC HiroseTakahiro IwataMasahiko HayakawaSatoshi HosodaO MoriHirotaka SawadaT ShimadaStefania SoldiniHajime YanoRyudo TsukizakiM OzakiY IijimaKazunori OgawaM FujimotoTra-Mi HoAurélie Moussi-SoffysRalf JaumannJean-Pierre BibringC KrauseFuyuto TeruiTakanao SaikiSatoru NakazawaYuichi TsudaPublished in: Science (New York, N.Y.) (2019)
The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present Hayabusa2 observations of Ryugu's shape, mass, and geomorphology. Ryugu has an oblate "spinning top" shape, with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates a high-porosity (>50%) interior. Large surface boulders suggest a rubble-pile structure. Surface slope analysis shows Ryugu's shape may have been produced from having once spun at twice the current rate. Coupled with the observed global material homogeneity, this suggests that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation. From these remote-sensing investigations, we identified a suitable sample collection site on the equatorial ridge.