MIPS observations of h and {chi} Persei

The data are combined with IRAC and 2MASS data to investigate ~616 sources from 1.25-24um. We use the long-baseline Ks-[24] color to identify two populations with IR excess indicative of circumstellar material: Be stars with 24um excess from optically thin free-free emission, and 17 fainter sources (J~14-15) with [24] excess consistent with a circumstellar disk.

The frequency of IR excess for the fainter sources increases from 4.5 to 24um. The IR excess is likely due to debris from the planet formation process. The wavelength-dependent behavior is consistent with an inside-out clearing of circumstellar disks.