Timescales of the Solar Protoplanetary Disk

We summarize geochemical, astronomical, and theoretical constraints on the lifetime of the protoplanetary disk. Absolute Pb-Pb-isotopic dating of CAIs in CV chondrites (4567.2 ± 0.7 m.y.) and chondrules in CV (4566.7 ± 1 m.y.), CR (4564.7 ± 0.6 m.y.), and CB (4562.7 ± 0.5 m.y.) chondrites, and relative Al-Mg chronology of CAIs and chondrules in primitive chondrites, suggest that high-temperature nebular processes, such as CAI and chondrule formation, lasted for about 3–5 m.y. Astronomical observations of the disks of low-mass, pre-main-sequence stars suggest that disk lifetimes are about 3–5 m.y.; there are only few young stellar objects that survive with strong dust emission and gas accretion to ages of 10 m.y. These constraints are generally consistent with dynamical modeling of solid particles in the protoplanetary disk, if rapid accretion of solids into bodies large enough to resist orbital decay and turbulent diffusion are taken into account.