发表机构
Aix-Marseille University; European Southern Observatory (ESO); Charles University; MIT; Northern Arizona University（艾克斯-马赛大学; 欧洲南方天文台; 查理大学; 麻省理工学院; 北亚利桑那大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究结合光谱拟合与动力学模型，识别了六颗任务目标近地天体的源族，并发现小尺寸S型复合近地天体成分分布接近陨石，为OC陨石来源提供了观测证据。
AI 中文摘要
背景。对近地天体（NEOs）的空间任务为研究其物理和成分特性提供了独特的机会。解释这些结果需要了解它们的来源，即它们在主小行星带中的源族。目标。我们旨在确定六颗已被或即将被空间任务访问的S型复合近地天体的家族来源，并使用MITHNEOS数据集研究更广泛的S型复合近地天体群体随尺寸变化的轨道行为。方法。我们将近红外光谱拟合与普通球粒陨石（OC）模拟物（经空间风化模型红化）相结合，使用约简χ²最小化，并与主近地天体源族的概率动力学图进行交叉验证。结果。我们为Eros、Itokawa、Apophis和Torifune确定了LL6-7球粒陨石和Flora家族；为Toutatis确定了LL3球粒陨石和Nysa家族；为Didymos-Dimorphos确定了L球粒陨石和Massalia家族。在存在原位观测（Itokawa和Eros）的情况下，分类结果一致。应用于更广泛的S型复合近地天体群体时，光谱分类和轨道性质分布与动力学模型大致一致。考虑观测偏差后，我们发现在小直径（≤100米）下，H型和L型天体的比例增加，而LL6-7型的比例减少，低倾角轨道与Massalia（L）和Koronis（H）家族的起源一致。结论。将光谱拟合与OC模拟物和动力学概率图相结合，能够稳健地识别单个近地天体的源族。在D~100米以下，S型复合近地天体的成分分布接近陨石坠落，为基于S型复合近地天体光谱测量的OC陨石源区的出现提供了直接观测证据。
英文摘要
Context. Space missions to near-Earth objects (NEOs) provide unique opportunities to study and characterise their physical and compositional properties. Interpreting these results requires knowledge of their provenance, i.e. their source family in the main asteroid belt. Aims. We aim to identify the family sources of six S-complex NEOs visited or soon to be visited by space missions, and to investigate the size-dependent orbital behaviour of the broader S-complex NEO population using the MITHNEOS dataset. Methods. We combine near-infrared spectral fitting with ordinary chondrite (OC) analogues reddened by a space-weathering model, using reduced $χ^2$ minimisation, and cross-validation with probabilistic dynamical maps of the main NEO source families. Results. We identify LL6-7 chondrites and the Flora family for Eros, Itokawa, Apophis, and Torifune; LL3 chondrites and the Nysa family for Toutatis; L chondrites and the Massalia family for Didymos-Dimorphos. Where in situ observations exist (Itokawa and Eros), the classifications are consistent. Applied to the broader S-complex NEO population, the spectral classification and orbital properties distributions are broadly consistent with dynamical models. Accounting for observational biases, we find that at small diameters ($\leq$100 m), the fractions of H- and L-type objects increase at the expense of LL6-7 types, with low-inclination orbits consistent with origins in the Massalia (L) and Koronis (H) families. Conclusions. Combining spectral fitting with OC analogues and dynamical probability maps robustly identifies the source families of individual NEOs. Below $D\sim$100 m, the compositional distribution of S-complex NEOs approaches that of meteorite falls, providing direct observational evidence, based on spectroscopic measurements of S-complex NEOs, of the emergence of the source regions of OC meteorites.
CommentsAccepted for publication in A&A. 12 pages, 10 figures
