Water circulation in Ryugu asteroid affected the distribution of nucleosynthetic isotope anomalies in returned sample.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37939187.
- Also identified by DOI 10.1126/sciadv.adi7048 and PMC identifier 10631728.
- Licence recorded as CC BY-NC.
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Abstract
Studies of material returned from Cb asteroid Ryugu have revealed considerable mineralogical and chemical heterogeneity, stemming primarily from brecciation and aqueous alteration. Isotopic anomalies could have also been affected by delivery of exogenous clasts and aqueous mobilization of soluble elements. Here, we show that isotopic anomalies for mildly soluble Cr are highly variable in Ryugu and CI chondrites, whereas those of Ti are relatively uniform. This variation in Cr isotope ratios is most likely due to physicochemical fractionation between <sup>54</sup>Cr-rich presolar nanoparticles and Cr-bearing secondary minerals at the millimeter-scale in the bulk samples, likely due to extensive aqueous alteration in their parent bodies that occurred [Formula: see text] after Solar System birth. In contrast, Ti isotopes were marginally affected by this process. Our results show that isotopic heterogeneities in asteroids are not all nebular or accretionary in nature but can also reflect element redistribution by water.