论文标题
Mithneos的辩护成分分布：近地下和主皮的小行星种群之间的全球匹配以及D型近地物的过量
The debiased compositional distribution of MITHNEOS: Global match between the near-Earth and main-belt asteroid populations and excess of D-type Near-Earth Objects
论文作者
论文摘要
我们报告了491个在NASA红外望远镜设施（IRTF）上收集的420个近地物（NEO）的420个新的近红外光谱测量值，这是MIT-HAWAII NEO SPECTROSCOCIC（MITHNEOS）的一部分。这些测量结果与先前发布的数据（Binzel等人，2019年）结合使用，并校正了偏见，以得出总体NEO人群的内在组成分布以及来自小行星带及其他各种逃生路线（ERS）的亚群。所得的分布很好地反映了小行星带的总体组成梯度，含量富含硅酸盐的（S-和Q-Type）体的分数降低，并增加了碳质（B-，C-，D-和P-Type）体的分数增加，这是越来越高的ER距离越高距离的功能。 NEOS及其预测的源群之间的密切组成匹配验证了用于识别ER的动态模型，并反对与小行星皮带的大小在〜5 km之间的大小下降到约100 m之间的任何强大组成变化。一个值得注意的例外来自5：2J的D型NEO，到较小的延伸，3：1J和NU6 ers，暗示存在主要皮带中大量的小型D型小行星。另外，这种过量可能表明由于空间风化而从D型表面到C和P型的优先光谱演变，或者与NEO空间中的其他光谱类型相比，D型物体碎片频率更高。在这项工作中，没有进一步的证据表明，主要带中存在碰撞家族，低于当前主要皮带调查的检测极限。
We report 491 new near-infrared spectroscopic measurements of 420 near-Earth objects (NEOs) collected on the NASA InfraRed Telescope Facility (IRTF) as part of the MIT-Hawaii NEO Spectroscopic Survey (MITHNEOS). These measurements were combined with previously published data (Binzel et al. 2019) and bias-corrected to derive the intrinsic compositional distribution of the overall NEO population, as well as of subpopulations coming from various escape routes (ERs) in the asteroid belt and beyond. The resulting distributions reflect well the overall compositional gradient of the asteroid belt, with decreasing fractions of silicate-rich (S- and Q-type) bodies and increasing fractions of carbonaceous (B-, C-, D- and P-type) bodies as a function of increasing ER distance from the Sun. The close compositional match between NEOs and their predicted source populations validates dynamical models used to identify ERs and argues against any strong composition change with size in the asteroid belt between ~5 km down to ~100 m. A notable exception comes from the over-abundance of D-type NEOs from the 5:2J and, to a lesser extend, the 3:1J and nu6 ERs, hinting at the presence of a large population of small D-type asteroids in the main belt. Alternatively, this excess may indicate preferential spectral evolution from D-type surfaces to C- and P-types as a consequence of space weathering, or to the fact that D-type objects fragment more often than other spectral types in the NEO space. No further evidence for the existence of collisional families in the main belt, below the detection limit of current main-belt surveys, was found in this work.
