Fingerprints of the Protosolar Cloud Collapse in the Solar System. II. Nucleosynthetic Anomalies in Meteorites

• Published in: The Astrophysical journal Vol. 884; no. 1; pp. 32 - 42
• Main Authors: Jacquet, Emmanuel, Pignatale, Francesco C., Chaussidon, Marc, Charnoz, Sébastien
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 10.10.2019; IOP Publishing; American Astronomical Society
• Subjects: Advection; Aluminum; Anomalies; Astrophysics; Calcium; Calcium-aluminum-rich inclusions; Carbonaceous chondrites; Chondrites; Cloud formation; Clouds; Collapse; Fossils; Heterogeneity; Isotope composition; Isotopes; Meteorites; meteorites, meteors, meteoroids; Meteoritic composition; Meteors & meteorites; Protoplanetary disks; Sciences of the Universe; Signatures; Solar system; stars: formation; meteorites; stars: formation; meteoroids; protoplanetary disks; meteors
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/ab38c1

The isotopic heterogeneity of the solar system shown by meteorite analyses is more pronounced for its earliest objects, the calcium-aluminum-rich inclusions (CAIs). This suggests that it was inherited from spatial variations in stardust populations in the protosolar cloud. We model the formation of the solar protoplanetary disk following its collapse and find that the solid-weighted standard deviation of different nucleosynthetic contributions in the disk is reduced by one order of magnitude compared to the protosolar cloud, whose successive isotopic signatures are fossilized by CAIs. The enrichment of carbonaceous chondrites in r-process components, whose proportions are inferred to have diminished near the end of infall, is consistent with their formation at large heliocentric distances, where the early signatures would have been preferentially preserved after outward advection. We also argue that thermal processing had little effect on the (mass-independent) isotopic composition of bulk meteorites for refractory elements.