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Description
We have obtained Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS) 24 micron and 70 micron observations of 215 nearby, Hipparcos B- and A-type common proper-motion single and binary systems in the nearest OB association, Scorpius-Centaurus. Combining our MIPS observations with those of other ScoCen stars in the literature, we estimate 24 micron B+A-type disk fractions of 17/67 (25^+6^_-5_%), 36/131 (27^+4^_-5_%), and 23/95 (24^+5^_-4_%) for Upper Scorpius (~11Myr), Upper Centaurus Lupus (~15Myr), and Lower Centaurus Crux (~17Myr), respectively, somewhat smaller disk fractions than previously obtained for F- and G-type members. We confirm previous IRAS excess detections and present new discoveries of 51 protoplanetary and debris disk systems, with fractional infrared luminosities ranging from LIR/L*=10^-6^ to 10^-2^ and grain temperatures ranging from Tgr=40 to 300K. In addition, we confirm that the 24 micron and 70 micron excesses (or fractional infrared luminosities) around B+A-type stars are smaller than those measured toward F+G-type stars and hypothesize that the observed disk property dependence on stellar mass may be the result of a higher stellar companion fraction around B- and A-type stars at 10-200AU. Finally, we note that the majority of the ScoCen 24 micron excess sources also possess 12 micron excess, indicating that Earth-like planets may be forming via collisions in the terrestrial planet zone at ~10-100Myr.
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