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

Bekaert, David V.; Auro, Maureen; Shollenberger, Quinn R.; Liu, Ming-Chang; Marschall, Horst; Burton, Kevin W.; Jacobsen, Benjamin; Brennecka, Gregory A.; McPherson, Glenn J.; von Mutius, Richard; Sarafian, Adam; Nielsen, Sune G.

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.

Citation

Bekaert, D. V., Auro, M., Shollenberger, Q. R., Liu, M., Marschall, H., Burton, K. W., …Nielsen, S. G. (2021). Fossil records of early solar irradiation and cosmolocation of the CAI factory: A reappraisal. Science Advances, 7(40), Article eabg8329. https://doi.org/10.1126/sciadv.abg8329

• Journal Article Type: Article
• Online Publication Date: Sep 29, 2021
• Publication Date: 2021
• Deposit Date: Oct 4, 2021
• Publicly Available Date: Oct 4, 2021
• Journal: Science Advances
• Publisher: American Association for the Advancement of Science
• Peer Reviewed: Peer Reviewed
• Volume: 7
• Issue: 40
• Article Number: eabg8329
• DOI: https://doi.org/10.1126/sciadv.abg8329