J/A+A/653/A57ivo://CDS.VizieR/J/A+A/653/A57doi:10.26093/cds/vizier.36530057CDSMarchis F.Jorda L.Vernazza P.Broz M.Hanus J.Ferrais M.,Vachier F.Rambaux N.Marsset M.Viikinkoski M.Jehin E.Benseguane S.,Podlewska-Gaca E.Carry B.Drouard A.Fauvaud S.Birlan M.Berthier J.,Bartczak P.Dumas C.Dudzinski G.Durech J.Castillo-Rogez J.,Cipriani F.Colas F.Fetick R.Fusco T.Grice J.Kryszczynska A.,Lamy P.Marciniak A.Michalowski T.Michel P.Pajuelo M.,Santana-Ros T.Tanga P.Vigan A.Witasse O.Yang B.2021-10-05T13:15:17Z2021-09-09T07:40:04ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frsolar-systemasteroidsThe recent estimates of the 3D shape of the M/Xe-type triple asteroid system (216) Kleopatra indicated a density of ~5g/cm^3^, which is by far the highest for a small Solar System body. Such a high density implies a high metal content as well as a low porosity which is not easy to reconcile with its peculiar "dumbbell" shape. Given the unprecedented angular resolution of the VLT/SPHERE/ZIMPOL camera, here, we aim to constrain the mass (via the characterization of the orbits of the moons) and the shape of (216) Kleopatra with high accuracy, hence its density. We combined our new VLT/SPHERE observations of (216) Kleopatra recorded during two apparitions in 2017 and 2018 with archival data from the W.M. Keck Observatory, as well as lightcurve, occultation, and delay-Doppler images, to derive a model of its 3D shape using two different algorithms (ADAM, MPCD). Furthermore, an N-body dynamical model allowed us to retrieve the orbital elements of the two moons as explained in the accompanying paper. The shape of (216) Kleopatra is very close to an equilibrium dumbbell figure with two lobes and a thick neck. Its volume equivalent diameter (118.75+/-1.40)km and mass (2.97+/-0.32)*10^18^kg (i.e., 56% lower than previously reported) imply a bulk density of (3.38+/-0.50)g/cm^3^. Such a low density for a supposedly metal-rich body indicates a substantial porosity within the primary. This porous structure along with its near equilibrium shape is compatible with a formation scenario including a giant impact followed by reaccumulation. (216) Kleopatra's current rotation period and dumbbell shape imply that it is in a critically rotating state. The low effective gravity along the equator of the body, together with the equatorial orbits of the moons and possibly rubble-pile structure, opens the possibility that the moons formed via mass shedding.2021A&A...653A..57Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/653/A57CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/653/A57https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/653/A57http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/653/A57https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/653/A57https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/653/A57http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/653/A57GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/653/A57/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/653/A57/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/653/A57/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/653/A57/list?GETtext/xml+votable180.050000true296.38336-0.143240.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/653/A576/22131 22275 22279-22280 30103 30107 30110 30114 30118https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/653/A57?format=asciidefaultJ/A+A/653/A57/listList of fits imagesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainscaleScale of the imagearcsec/pixinstr.scaledoubleNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintObs.dateObservation datestime.epoch;obsnullablesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.ref.urlchar