Astrophys. J., 738, 122 (2011/September-2)
A Magellan MIKE and Spitzer MIPS study of 1.5-1.0 M☉ stars in Scorpius-Centaurus.
CHEN C.H., MAMAJEK E.E., BITNER M.A., PECAUT M., SU K.Y.L. and WEINBERGER A.J.
Abstract (from CDS):
We obtained Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS) 24 µm and 70 µm observations of 182 nearby, Hipparcos F- and G-type common proper motion single and binary systems in the nearest OB association, Scorpius-Centaurus. We also obtained Magellan/MIKE R ∼ 50,000 visual spectra at 3500-10500 Å for 181 candidate ScoCen stars in single and binary systems. Combining our MIPS observations with those of other ScoCen stars in the literature, we estimate 24 µm F+G-type disk fractions of 9/27 (33%±11%), 21/67 (31%±7%), and 25/71 (35%±7%) for Upper Scorpius (∼10 Myr), Upper Centaurus Lupus (∼15 Myr), and Lower Centaurus Crux (∼17 Myr), respectively. We confirm previous IRAS and MIPS excess detections and present new discoveries of 41 protoplanetary and debris disk systems, with fractional infrared luminosities ranging from LIR/L*= 10–5 to 10–2 and grain temperatures ranging from Tgr= 40-300 K. We searched for an increase in 24 µm excess at an age of 15-20 Myr, consistent with the onset of debris production predicted by coagulation N-body simulations of outer planetary systems. We found such an increase around 1.5 M☉ stars but discovered a decrease in the 24 µm excess around 1.0 M☉stars. We additionally discovered that the 24 µm excess around 1.0 M☉ stars is larger than predicted by self-stirred models. Finally, we found a weak anti-correlation between fractional infrared luminosity (LIR/L*) and chromospheric activity (R'HK), that may be the result of differences in stellar properties, such as mass, luminosity, and/or winds.
circumstellar matter - infrared: planetary systems - planets and satellites: formation - protoplanetary disks - stars: kinematics and dynamics - stars: solar-type
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<Available at CDS (J/ApJ/738/122): table1.dat table2.dat table4.dat refs.dat>
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