IR photometry for members of Upper Sco

We have used these data to identify the members that exhibit excess emission from circumstellar disks and estimate the evolutionary stages of these disks. Through this analysis, we have found ~50 new candidates for transitional, evolved, and debris disks.

The fraction of members harboring inner primordial disks is <~10% for B-G stars (M>1.2M_{sun}_) and increases with later types to a value of ~25% at >~M5 (M<~0.2 M_{sun}_), in agreement with the results of previous disk surveys of smaller samples of Upper Sco members. These data indicate that the lifetimes of disks are longer at lower stellar masses and that a significant fraction of disks of low-mass stars survive for at least ~10Myr.