A Spitzer Study of Dusty Disks in the Scorpius-Centaurus OB Association
Abstract
We obtained Spitzer Space Telescope Multiband Imaging Photometer for
Spitzer (MIPS) 24 micron and 70 micron observations of 183 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 Angstrom 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 micron F+G-type disk fractions of 9/27 (33% ± 11%), 23/68 (34% ± 7%), and 22/71 (31% ± 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 proto-planetary and debris disk systems, with fractional infrared luminosities ranging from L<emph type="inferior">IR</emph>/L<emph type="inferior">*</emph> = 10<emph type="superior">-5</emph> - 10<emph type="superior">-2</emph> and grain temperatures ranging from T<emph type="inferior">gr</emph> = 40 - 300 K. We searched for an increase in 24 micron 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<emph type="inferior">sun</emph> stars but discovered a decrease in the 24 micron excess around 1.0 M<emph type="inferior">sun</emph>stars. We additionally discovered that the 24 micron excess around 1.0 M<emph type="inferior">sun</emph> stars is larger than predicted by self-stirred models. Finally, we found a weak anti-correlation between fractional infrared luminosity (L<emph type="inferior">IR</emph>/L<emph type="inferior">*</emph>) and chromospheric activity (R'<emph type="inferior">HK</emph>), that may be the result of differences in stellar luminosity and/or activity.- Publication:
-
AAS/Division for Extreme Solar Systems Abstracts
- Pub Date:
- September 2011
- Bibcode:
- 2011ESS.....2.3803C