Astromat

Accelerator mass spectrometry analysis of 26Al concentrations in six sub-samples from aggregate sample OEX-803014-0. The samples include one bulk aggregate sample, OREX-803047-0, of almost 10 mg, and 5 individual mm-sized particles (OREX-803048-0, OREX-803049-0, OREX-803050-0, OREX-803051-0, OREX-803052-0), each one weighing less than 1 mg. For comparison, we also measured two aliquots of the Orgueil CI chondrite. Each sample was dissolved in HF/HNO3 and a small aliquot of the dissolved sample was taken for chemical analysis by ICP-OES. The 26Al concentrations in the particles range from ~20 to ~26 dpm/kg, compared to a 26Al concentration of ~21 dpm/kg in the aggregate sample. Combined with the 10Be data, these results constrain the cosmic-ray exposure age of the samples to at least a few Myr near the sufrace of asteroid Bennu.