Geoffrey S. Mathews, Jonathan P. Williams, Francois Ménard, Neil Phillips, Gaspard Duchêne, Christophe Pinte
We present deep 1.2 millimeter photometry of 37 stars in the young (5 Myr)
Upper Scorpius OB association, sensitive to ~4 x 10^-3 Mjup 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
x 10^-3 -- 1.0 x 10^-1 Mjup. 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 Halpha 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
View original:
http://arxiv.org/abs/1111.0101
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