Pyroxene mineralogies of near‐Earth vestoids
Pyroxene mineralogies of near‐Earth vestoids
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近地类火山岩的辉石矿物学
DOI：
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发表时间：
2009
期刊：
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通讯作者：
R. Binzel
中科院分区：
文献类型：
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作者：
T. Burbine;P. Buchanan;T. Dolkar;R. Binzel
摘要-我们已经计算了七个近地小行星（NEAs）的辉石矿物学，其反射光谱与HED（霍瓦蒂岩，eucrites和diogenites）相似。使用两套不同的公式（Gaffey等人，2002年; Burbine等人，2007年）计算近地小行星带I和带II中心的辉石矿物学。谱带中心已被调整，以补偿小行星表面的低温。所有从Gaffey等人（2002年）公式和Burbine等人（2007年）公式得出的矿物学都有重叠。衍生的硅灰石（Wo）含量非常相似，差异仅为约1摩尔%。衍生的硅铁（Fs）含量仅相差3至8摩尔%。所有七个近地玻璃体的辉石矿物学都与eucrites或howardites一致。这些物体中没有一个含有与闪长岩一致的辉石矿物。缺乏具有类似于闪长岩的辉石矿物学的近地玻璃体可能表明很难产生主要由闪长岩材料组成的相当大的（公里大小或更大）的物体，这表明这些物体是混合喷出物的碎石堆。
Abstract— We have calculated pyroxene mineralogies of seven near‐Earth asteroids (NEAs) with reflectance spectra similar to HEDs (howardites, eucrites, and diogenites). Two different sets of formulas (Gaffey et al. 2002; Burbine et al. 2007) are used to calculate the pyroxene mineralogies of the NEAs from their Band I and II centers. The band centers have been adjusted to compensate for the low temperatures on the asteroid surfaces. All of the derived mineralogies from the Gaffey et al. (2002) formulas and the Burbine et al. (2007) formulas overlap. The derived wollastonite (Wo) contents are very similar with differences being only approximately 1 mol%. The derived ferrosilite (Fs) contents differ by only 3 to 8 mol%. The determined pyroxene mineralogies for all seven near‐Earth vestoids are consistent with eucrites or howardites. None of the objects have pyroxene mineralogies consistent with diogenites. The absence of near‐Earth vestoids with pyroxene mineralogies similar to diogenites may indicate that it is difficult to produce sizeable (km‐sized or larger) bodies that are predominantly composed of diogenitic material, suggesting these objects are rubble piles of mixed ejecta.