Variations in color and reflectance on the surface of asteroid (101955) Bennu.
Daniella N DellaGiustinaK N BurkeKevin J WalshP H SmithDathon R GolishEdward B BierhausRonald-Louis BallouzT L BeckerHumberto CampinsEri TatsumiK YumotoSeiji SugitaJ D Prasanna DeshapriyaEdward A CloutisB E ClarkAmanda R HendrixA SenM Al AsadMichael G DalyD M ApplinC AvdellidouM Antonietta BarucciK J BeckerCarina A BennettWilliam F BottkeJ I BrodbeckHarold C ConnollyMarco Delbo'Julia de LeónC Y Drouet d'AubignyK L EdmundsonSonia FornasierVictoria E HamiltonP H HasselmannCarl W HergenrotherE S HowellErica R JawinHannah H KaplanL Le CorreLucy F LimJian-Yang LiPatrick MichelJ L MolaroMichael C NolanJ NolauMaurizio PajolaA ParkinsonM PopescuN A PorterBashar RizkJuan Luis RizosAndrew J RyanBenjamin RozitisN K ShultzAmy A SimonD TrangR B Van AukenC W V WolnerDante S LaurettaPublished in: Science (New York, N.Y.) (2020)
Visible-wavelength color and reflectance provide information about the geologic history of planetary surfaces. Here we present multispectral images (0.44 to 0.89 micrometers) of near-Earth asteroid (101955) Bennu. The surface has variable colors overlain on a moderately blue global terrain. Two primary boulder types are distinguishable by their reflectance and texture. Space weathering of Bennu surface materials does not simply progress from red to blue (or vice versa). Instead, freshly exposed, redder surfaces initially brighten in the near-ultraviolet region (i.e., become bluer at shorter wavelengths), then brighten in the visible to near-infrared region, leading to Bennu's moderately blue average color. Craters indicate that the time scale of these color changes is ~105 years. We attribute the reflectance and color variation to a combination of primordial heterogeneity and varying exposure ages.