Séminaire IPAG

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A survey of hydrated phosphates in returned Ryugu and Bennu samples reveals divergent alteration histories

jeudi 26 février 2026 - 11h00

Rachel Sheppard - IAS
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Infrared spectra of returned samples from Bennu and Ryugu reveal contrasting abundances of hydrated phosphate phases despite broadly similar bulk compositions. Bennu exhibits a >4× higher abundance of hydrated phosphates than Ryugu, indicating different extents of fluid-mediated phosphate reorganization. We present a Ca-controlled alteration pathway linking carbonate formation to precipitation of metastable Mg-phosphate phases followed by apatite, with implications for phosphorus mobility and prebiotic chemistry in primitive asteroids.

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