SSP seminar

A Spitzer Study of Dusty Disks in the Scorpius-Centaurus OB Association II: Disk Demographics for F- and G-type Members

Christine Chen (STScI)

Monday 4th April 2011, 12:00 noon
Pratt conference room, 60 Garden Street

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 near est OB association, Scorpius-Centaurus. We also obtained Magellan/MIKE R~50,000 visual spectra at 3500 Angstrom - 10500 Angstrom for 183 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 (~5 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 LIR/L* = 1e-5 - 1e-2 and grain temperatures ranging from Tgr = 40 - 300 K. We searched for a peak in the fractional infrared luminosity at an age of 15-20 Myr, consistent with the onset of debris production predicted by coagulation N-body simulations of outer planetary systems, but were unable to detect such a peak. We discovered a weak anti-correlation between fractional infrared luminosity (LIR/L*) and chromospheric activity (R'HK), that may be the result of differences in stellar luminosity and/or activity.


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