Constraints on the Origin of Chondrules and CAIs from Short-lived and Long-lived Radionuclides

In order to understand the timing of events in the early solar system, we rely on the radio-nuclide-based chronometers applied to materials in primitive meteorites. Because the time scale of early-solar system evolution was on the order of a few million years (Myr), we focus on so-called "short-lived radionuclides" with mean lives of less than 10 Myr (Table 1), as well as on the long-lived U-Pb system where high precision 207Pb-206Pb ages are applied. Note that the validity of some systems as chronometers (e.g., Be-B, Fe-Ni) has yet to be established. We summarize literature data for chondrules and CAIs and discuss how these chronometers constrain formation time scales in the early solar system.