We have obtained Spitzer Space Telescope Multiband Imaging Photometer for Spitzer ( MIPS ) 24 \mu m and 70 \mu m 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 \mu m B+A-type disk fractions of 17/67 ( 25 ^ { +6 } _ { -5 } % ) , 36/131 ( 27 ^ { +4 } _ { -4 } % ) , and 23/95 ( 24 ^ { +5 } _ { -4 } % ) for Upper Scorpius ( \sim 11 Myr ) , Upper Centaurus Lupus ( \sim 15 Myr ) , and Lower Centaurus Crux ( \sim 17 Myr ) , 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 L _ { IR } / L _ { * } = 10 ^ { -6 } to 10 ^ { -2 } and grain temperatures ranging from T _ { gr } = 40 - 300 K. In addition , we confirm that the 24 \mu m and 70 \mu m 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 - 200 AU and/or the presence of Jupiter-mass companions in the disks around F- and G-type stars .
Finally , we note that the majority of the ScoCen 24 \mu m excess sources also possess 12 \mu m excess , indicating that Earth-like planets may be forming via collisions in the terrestrial planet zone at \sim 10 - 100 Myr .