Astrophys. J., 756, 133 (2012/September-2)
A Spitzer MIPS study of 2.5-2.0M☉ stars in Scorpius-Centaurus.
CHEN C.H., PECAUT M., MAMAJEK E.E., SU K.Y.L. and BITNER M.
Abstract (from CDS):
We have obtained Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS) 24 µm and 70 µm 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 µm 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 (∼11 Myr), Upper Centaurus Lupus (∼15 Myr), and Lower Centaurus Crux (∼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 LIR/L *= 10–6 to 10–2 and grain temperatures ranging from Tgr= 40 to 300 K. In addition, we confirm that the 24 µm and 70 µm 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. Finally, we note that the majority of the ScoCen 24 µm excess sources also possess 12 µm excess, indicating that Earth-like planets may be forming via collisions in the terrestrial planet zone at ∼10-100 Myr.
circumstellar matter - infrared: planetary systems - infrared: stars - open clusters and associations: individual (Upper Scorpius, Lower Centaurus, Crux, Upper Centaurus) - planetary systems - planets and satellites: formation
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<Available at CDS (J/ApJ/756/133): table1.dat table2.dat table3.dat refs.dat>
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