Reading: MacPherson et al. (1988)
1. At what temperature did CAIs form in the solar nebula, assuming an equilibrium model? To answer this question, use your knowledge of the primary phases found in CAIs together with the condensation sequence reproduced in the accompanying glossary.
2. Of the various processes that have affected CAIs (sections 10.3.7 to 10.3.14), consider how strong the evidence for these processes seems to be. Create a table which lists the process in one column, and in another column, your evaluation of whether the process is "strongly supported", "somewhat supported", or "equivocal".
3. BONUS QUESTION (ANSWER IF YOU CAN): CAIs are often enriched in refractory elements (those with high 50% condensation temperatures) relative to CI chondrite "cosmic abundances" by a factor of ~20x. Rare-earth-elements, which are used to classify CAIs, are good examples of such refractory elements. If CAIs formed by condensation in a system with overall cosmic composition, why are refractory elements enriched, and what is the significance of the factor 20x enrichment in refractory elements?