We present deep 1.2 millimeter photometry of 37 stars in the young ( 5 Myr ) Upper Scorpius OB association , sensitive to \sim 4 \times 10 ^ { -3 } M _ { Jup } Â of cool millimeter dust .
Disks around four low- and solar-mass stars are detected , as well as one debris disk around an intermediate mass star , with dust masses ranging from 3.6 \times 10 ^ { -3 } – 1.0 \times 10 ^ { -1 } M _ { Jup } .
The source with the most massive disk exhibits a transition-disk spectral energy distribution .
Combining our results with previous studies , we find the millimeter-detection fraction of Class II sources has significantly decreased from younger ages , and comparison with near-infrared and H \alpha measurements indicates the present disks have undergone significant evolution in composition or structure at all radii .
The disks of Upper Scorpius represent the tail-end of the depletion of primordial disks ; while a few near-solar mass stars may still sustain giant planet formation , this process has finished around higher mass stars .