Fossil records of early solar irradiation and cosmolocation of the CAI factory: A reappraisal.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34586847.
- Also identified by DOI 10.1126/sciadv.abg8329 and PMC identifier 8480928.
- Licence recorded as CC BY-NC.
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Abstract
Calcium-aluminum–rich inclusions (CAIs) in meteorites carry crucial information about the environmental conditions of the nascent Solar System prior to planet formation. Based on models of <sup>50</sup>V–<sup>10</sup>Be co-production by in-situ irradiation, CAIs are considered to have formed within ~0.1 AU from the proto-Sun. Here, we present vanadium (V) and strontium (Sr) isotopic co-variations in fine- and coarse-grained CAIs and demonstrate that kinetic isotope effects during partial condensation and evaporation best explain V isotope anomalies previously attributed to solar particle irradiation. We also report initial excesses of <sup>10</sup>Be and argue that CV CAIs possess essentially a homogeneous level of <sup>10</sup>Be, inherited during their formation. Based on numerical modeling of <sup>50</sup>V–<sup>10</sup>Be co-production by irradiation, we show that CAI formation during protoplanetary disk build-up likely occurred at greater heliocentric distances than previously considered, up to planet-forming regions (~1AU), where solar particle fluxes were sufficiently low to avoid substantial in-situ irradiation of CAIs.