Predicted IR excesses for protoplanetary disks

These objects contain <=3%-4% of the initial mass in solid material. Collisional cascades produce debris disks with maximum luminosity ~2x10^-3^ times the stellar luminosity. The peak 24um excess varies from ~1% times the stellar photospheric flux for 1M_{sun}_ stars to ~50 times the stellar photospheric flux for 3M_{sun}_ stars.

The peak 70-850um excesses are ~30-100 times the stellar photospheric flux. For all stars, the 24-160um excesses rise at stellar ages of 5-20Myr, peak at 10-50Myr, and then decline. The decline is roughly a power law, f{propto}t^-n^ with n~0.6-1.0.

This predicted evolution agrees with published observations of A-type and solar-type stars. The observed far-IR color evolution of A-type stars also matches model predictions.