Fossil records of early solar irradiation and cosmolocation of the CAI factory: A reappraisal.

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 ⁵⁰V–¹⁰Be 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 ¹⁰Be and argue that CV CAIs possess essentially a homogeneous level of ¹⁰Be, inherited during their formation. Based on numerical modeling of ⁵⁰V–¹⁰Be 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.

SUBMITTER: Bekaert DV 

PROVIDER: S-EPMC8480928 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature