Volatile-rich asteroids are crucial to understanding the transport of water and organics to the terrestrial planet forming region in the early Solar System. Observations of two such asteroids by Hayabusa2 and Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) suggest a relationship between these bodies and CI, CM, and CY chondrites. To confirm this, meteorite spectra need to be collected under appropriate conditions for comparison with asteroid observations. We report midinfrared (MIR) emissivity spectra (5.5–50 μm) obtained under ambient and simulated asteroid environment conditions and near-infrared (NIR) reflectance spectra (2–5 μm) of CM and CY chondrite fine-particulate (<35 μm) powders for which bulk mineralogy was determined using X-ray diffraction. Reflectance spectra show a 3 μm feature associated with -OH/H₂O that shifts from shorter (∼2.72 μm) to longer (∼2.90 μm) wavelengths and develops a rounder shape and reduced band area with increasing thermal metamorphism. In the MIR, the transparency feature (TF) and features in the Si-O bending region (>15 μm) can be used to infer the relative degree of aqueous alteration, and to resolve the effects of aqueous and thermal alteration, when combined with NIR spectral parameters. The MIR spectra of metamorphosed CY chondrites are distinct from CM chondrite spectra, including a plateau around the Christiansen feature (∼8.00–12.50 μm) and features at longer wavelengths in the Si-O bending region (e.g., ∼25.50 μm compared to ∼24.30 μm in the CM spectra). We additionally report potential implications of the spectra and parameters determined in this study for the results from Hayabusa2 and OSIRIS-REx.

中文翻译：

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模拟小行星条件下水和热改变的 CM、CM-An 和 CY 球粒陨石的光谱研究，以与 OSIRIS-REx 和 Hayabusa2 观测进行比较

富含挥发性物质的小行星对于了解早期太阳系中水和有机物向类地行星形成区域的运输至关重要。Hayabusa2 和 Origins、光谱解释、资源识别、安全、风化层探索者 (OSIRIS-REx) 对两颗这样的小行星的观察表明这些天体与 CI、CM 和 CY 球粒陨石之间存在关系。为了证实这一点，需要在适当的条件下收集陨石光谱，以便与小行星观测结果进行比较。我们报告了在环境和模拟小行星环境条件下获得的中红外 (MIR) 发射率光谱 (5.5-50 μm) 以及 CM 和 CY 球粒陨石细颗粒 (<35 μm) 的近红外 (NIR) 反射光谱（2-5 μm）使用 X 射线衍射确定散装矿物学的粉末。₂O 从较短的 (~2.72 μm) 转变为更长的 (~2.90 μm) 波长，并随着热变质作用的增加而形成更圆的形状和减小的带面积。在 MIR 中，透明特征 (TF) 和 Si-O 弯曲区域 (>15 μm) 中的特征可用于推断水蚀变的相对程度，并在结合使用时解决水蚀和热蚀变的影响近红外光谱参数。变质 CY 球粒陨石的 MIR 光谱与 CM 球粒陨石光谱不同，包括 Christiansen 特征周围的平台（~8.00-12.50 μm）和 Si-O 弯曲区域中更长波长的特征（例如，~25.50 μm 与~24.30 μm 在 CM 光谱中）。我们还报告了本研究中确定的光谱和参数对 Hayabusa2 和 OSIRIS-REx 结果的潜在影响。