Two papers on CAIs from Murchison published

Fri, 08/19/2016 - 08:54 -- Anonymous (not verified)

University of Chicago postdoctoral scientist Levke Kööp, Robert A. Pritzker Associate Curator Philipp Heck, and colleagues from the Universities of Chicago, Wisconsin, and Hawaii, recently published two articles in the journal Geochimica and Cosmochimica Acta. The focus of their work was on some of the first materials that formed in the Solar System, i.e., inclusions in meteorites rich in the mineral hibonite. By studying these early-formed objects, the team aimed to find clues about the type of stars that contributed matter to the Solar System, and thus improve understanding of different stages in the evolution of the Solar System. In the first study, the team reports that these early-formed objects have a wide range of anomalous compositions, which suggest that the Solar System inherited material from a number of stars (e.g., a rare type of supernova called type Ia). The results indicate that such material was not mixed to the point of homogeneity before the Solar System formed. For the second study, the authors analyzed meteoritic inclusions that contained hibonite as well as the mineral spinel. They found that these objects are less anomalous than previously thought and probably formed at a later stage in Solar System history, after mixing had largely homogenized materials in the protoplanetary disk (the rotating disk of dust and gas that surrounds the core of a developing solar system). This research is part of Levke’s dissertation, which she defended in May 2016. Levke identified the hibonite-rich inclusions in the famous Murchison meteorite, which is part of The Field Museum meteorite collection. She prepared the samples for analysis in the Robert A. Pritzker Center’s Cosmochemistry Laboratory and studied them with the scanning electron microscopes at The Field Museum and the University of Chicago and ion probes at the University of Wisconsin and University of Hawaii.

Links to the publications:

  • New constraints on the relationship between 26Al and oxygen, calcium, and titanium isotopic variation in the early Solar System from a multielement isotopic study of spinel-hibonite inclusions
  • A link between oxygen, calcium and titanium isotopes in 26Al-poor hibonite-rich CAIs from Murchison and implications for the heterogeneity of dust reservoirs in the solar nebula