标题： 盖亚探测早期形成安山质小行星地壳 显示英文标题

标题： Gaia search for early-formed andesitic asteroidal crusts

摘要： 背景。 安山岩质陨石是有史以来已知最古老的无球粒陨石之一。 它们记录了大约45.65亿年前原始星子中的火山事件和地壳形成期。 然而，到目前为止，在小行星群体中尚未发现这些陨石的类似物。 目标。 我们使用Gaia DR3光谱数据集在小行星群体中寻找与安山岩质陨石Erg Chech 002的光谱类似物。 方法。 为了确定哪些小行星的光谱与Erg Chech 002最相似，我们首先确定了Gaia DR3小行星的光谱参数（光谱斜率和I带深度），并将它们与不同样品陨石的光谱参数进行了比较。 此外，我们还对Erg Chech 002和Gaia DR3小行星数据进行了光谱曲线匹配，并比较了两种方法的结果。 结果。 我们发现有51颗主小行星带小行星的可见光光谱与Erg Chech 002的光谱相似，而91颗小行星的光谱与陨石的空间风化光谱相似，分别占整个Gaia DR3小行星光谱数据集的0.08%和0.15%。 与实验室样品陨石最匹配的小行星主要位于内主小行星带，而与空间风化陨石模型匹配的对象在小行星带上的分布稍显分散。 结论。 尽管我们找到了可能与Erg Chech 002相匹配的小行星，但这些小行星极为稀少。 此外，单一的可见光光谱并不能完全诊断出Erg Chech 002样的成分。 近红外光谱将是确认（或排除）Erg Chech 002与候选小行星群之间光谱匹配的重要手段。 显示英文摘要

摘要： Context. Andesitic meteorites are among the oldest achondrites known to date. They record volcanic events and crust formation episodes in primordial planetesimals that took place about 4.565 Myr ago. However, no analogue for these meteorites has been found in the asteroid population to date. Aims. We searched for spectroscopic analogues of the andesitic meteorite Erg Chech 002 in the asteroid population using the Gaia DR3 spectral dataset. Methods. In order to identify which asteroids have the most similar spectrum to Erg Chech 002, we first determined the spectral parameters of Gaia DR3 asteroids (spectral slope and Band I depth) and compared them to the spectral parameters of different samples of the meteorite. In addition, we performed a spectral curve matching between Erg Chech 002 and Gaia DR3 asteroid data, and we compared the results of both methods. Results. We found that 51 main-belt asteroids have a visible spectrum similar to the one of Erg Chech 002, and 91 have a spectrum similar to the space-weathered spectra of the meteorite, corresponding to 0.08 and 0.15% of the whole Gaia DR3 dataset of asteroids with spectra, respectively. The asteroids that best match the laboratory samples of the meteorite are mostly located in the inner main belt, while the objects matching the space-weathered meteorite models show slightly more scattering across the belt. Conclusions. Despite the fact that we find asteroids that potentially match Erg Chech 002, these asteroids are extremely rare. Moreover, a visible spectrum alone is not completely diagnostic of an Erg Chech 002-like composition. Near-infrared spectra will be important to confirm (or rule out) the spectral matches between Erg Chech 002 and the candidate asteroid population.