近地小行星太空风化光谱效应的模拟实验研究

Laboratory Simulation of the Space Weathering Effects on Reflectance Spectra of Near-Earth Asteroids

本文选取3种类型的陨石分别进行脉冲激光辐照实验,模拟距离太阳1个天文单位(1 AU)处,10亿年(1 Ga)期间微陨石轰击的太空风化作用对E型、S型、C群等近地小行星光谱特征的改造。结果显示,激光辐照后,顽辉石无球粒陨石光谱的可见光波段反射率降低且近红外斜率增加,与E型小行星光谱改造特征一致;普通球粒陨石的可见光-近红外波段反射率均降低、吸收深度变浅且近红外斜率增加,与S型小行星光谱改造特征一致;CV3型碳质球粒陨石和CO3型碳质球粒陨石在激光辐照后可见光波段反射率降低,但近红外波段反射率升高,吸收深度变浅且近红外斜率增加,与贫挥发分的C群小行星光谱改造特征一致;CM2碳质陨石在激光辐照后,可见光波段反射率增加,但近红外波段反射率及近红外斜率降低,与富挥发分的C群小行星光谱改造特征一致。研究结果可为近地小行星探测任务备选目标的确定、光谱遥感数据以及表面物质演化过程的反演提供一定的参考。

In this paper,three types of meteorites were selected to have been undertaken pulse laser irradiation experiments for simulating the alteration effects on spectra of E-,M-,and C-group Near-Earth Asteroids by the space weathering resulted from the micrometeorite impact on their surfaces at an assumed place of 1 astronomical unit(1 AU)away from the Sun for 1 billion years(1 Ga).The results show that the laser irradiated aubrite has relatively low reflectivity of visible band but relatively high slope of near-infrared band in its spectrum,which is consistent with that of the weathered E-type asteroid. The ordinary chondrite has relatively low reflectivity of visible and near-infrared bands,relatively shallowadsorption but relatively high slope of near-infrared band in its spectrum,which is consistent with that of the weatheredS-type asteroid. The laser irradiated CV3 and CO3 carbonaceous chondrites have relatively low reflectivity of visibleband but high reflectivity of near-infrared band,relatively shallow adsorption but high slope of near-infrared band intheir spectra,which are consistent with that of the weathered volatile-poor C-group asteroid. The laser irradiated CM2carbonaceous chondrite has relatively high reflectivity of visible band but relative low reflectivity and slope of near-infraredband in its spectrum,which is consistent with that of the weathered volatile-rich C-group asteroid. The research mayprovide a certain reference and support for choosing suitable asteroid as target for the future Near-Earth Asteroid explorationmission,interpreting spectral remote sensing data,and understanding the evolution process of asteroid surface materials.