Widespread carbon-bearing materials on near-Earth asteroid (101955) Bennu

Amy A. Simon, Hannah H. Kaplan, Victoria E. Hamilton, Dante S. Lauretta, Humberto Campins, Joshua P. Emery, M. Antonietta Barucci, Daniella N. DellaGiustina, Dennis C. Reuter, Scott A. Sandford, Dathon R. Golish, Lucy F. Lim, Andrew Ryan, Benjamin Rozitis, Carina A. Bennett

Science 08 Oct 2020:
eabc3522, Published Online: 08 Oct 2020


“(101955) Bennu is a dark asteroid on an Earth-crossing orbit, thought to have assembled from the fragments of an ancient collision. We use spatially-resolved visible and near-infrared spectra of Bennu to investigate its surface properties and composition. In addition to a hydrated phyllosilicate band, we detect a ubiquitous 3.4-micron absorption feature, which we attribute to a mix of organic and carbonate materials. The shape and depth of this absorption feature vary across Bennu’s surface, spanning the range seen among similar main-belt asteroids. Its distribution does not correlate with temperature, reflectance, spectral slope, or hydrated minerals, although some of those characteristics correlate with each other. The deepest 3.4-micron absorptions occur on individual boulders. The variations may be due to differences in abundance, recent exposure, or space weathering.”