Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD, USA.
Southwest Research Institute, Boulder, CO, USA.
Science. 2020 Nov 6;370(6517). doi: 10.1126/science.abc3522. Epub 2020 Oct 8.
Asteroid (101955) Bennu is a dark asteroid on an Earth-crossing orbit that is 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-micrometer 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. The distribution of the absorption feature does not correlate with temperature, reflectance, spectral slope, or hydrated minerals, although some of those characteristics correlate with each other. The deepest 3.4-micrometer absorptions occur on individual boulders. The variations may be due to differences in abundance, recent exposure, or space weathering.
贝努是一颗位于地球穿越轨道上的暗小行星，据认为它是由一次古老的碰撞碎片组装而成的。我们使用贝努的空间分辨可见和近红外光谱来研究其表面特性和成分。除了水合层状硅酸盐带之外，我们还检测到一个普遍存在的 3.4 微米吸收特征，我们将其归因于有机和碳酸盐材料的混合物。该吸收特征的形状和深度在贝努的表面上变化，跨越了在类似主带小行星中看到的范围。该吸收特征的分布与温度、反射率、光谱斜率或水合矿物无关，尽管这些特征中的一些相互关联。最深的 3.4 微米吸收发生在单个巨石上。这些变化可能是由于丰度、最近暴露或空间风化的差异造成的。
