Post by Stephanie Soquet

The Lucy flyby of (52246) Donaldjohanson: A bilobed asteroid with tumbling rotation. Abstract:"The main belt asteroid (52246) Donaldjohanson (DJ) is a likely member of the Erigone asteroid family. This implies that DJ is a fragment of a larger parent body that was destroyed in a collision about 155 million years ago. We report observations taken during a flyby of DJ by the Lucy spacecraft. We found that DJ is composed of two heavily cratered lobes, connected by a smoother neck, with overall dimensions 8.8 km by 4.4 km by 3.1 km. The crater density is consistent with the Erigone family’s age, except for craters <0.4 km, which have been preferentially erased. DJ rotates slowly in a tumbling state, likely owing to spin-down by radiative forces. Surface spectra show iron-bearing phyllosilicates, indicating moderate aqueous evolution on the parent body." 1 Southwest Research Institute, Boulder, CO, US 2 NASA Goddard Space Flight Center US 3 Planetary Science Institute, US 4 NASA Headquarters US 5 Johns Hopkins University Applied Physics Laboratory US 6 School of Earth and Space Exploration, ASU,Tempe US 7 Lockheed Martin Space, CO, US 8 Dep of Aeronautics and Astronautics, MIT, Cambridge, MA, US 9 Dep of Physics,University of Central Florida, Orlando, FL, US 10 Div of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, US 11 Lowell Observatory, Flagstaff, AZ, US 12 Dep of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, US 13 Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, UK 14 NationalOptical-Infrared Astronomy Research Laboratory, National Science Foundation, Tucson, AZ, US 15 London Stereoscopic Company, London, UK 16 Institute of Space Research, German AerospaceCenter, Berlin, Germany 17 Fifth West Consulting, Niwot, CO, US 18 Freies Institut für Planetenforschung Köln, Cologne, Germany. 19 Space Sector, Southwest Research Institute, Boulder, CO, US 20 Dep of Astronomy, Department of Geological, Environmental and Planetary Sciences, University of Maryland, College Park, MD, US 21 Astronomical Institute, Charles University,Prague, Czech Republic. 22 Université Côte d’Azur, Observatoire de la Côte d’Azur, French National Center for Scientific Research, Laboratoire Lagrange, Nice, France. 23 CNES, Paris, France. 24 Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, HI, US 25 Daniel Guggenheim School of Aerospace Engineering, GeorgiaInstitute of Technology, Atlanta, GA, US 26 Center for Earth and Planetary Studies, Smithsonian National Air and Space Museum, Washington, DC, US 27 JPL, California Institute of Technology, Pasadena, CA, US 28 Dep of Astronomy, University of Virginia, Charlottesville, VA, US 29 Flight Dynamics Interplanetary Department, KinetX, Littleton, CO, US 30 Center for Imaging Science, Rochester Institute of Technology, Rochester, NY, US 31Stellar Solutions, Denver, CO, US