The Spitzer c2d survey of weak-line T Tauri stars. III. The transition from primordial disks to debris disks.

Wahhaj, Zahed and Cieza, Lucas and Koerner, David W. and Stapelfeldt, Karl R. and Padgett, Deborah L. and Case, April and Keller, James R. and Merin, Bruno and Evans, Neal J. and Harvey, Paul and Sargent, Anneila and van Dishoeck, Ewine F. and Allen, Lori and Blake, Geoff and Brooke, Tim and Chapman, Nicholas and Mundy, Lee and Myers, Philip C. (2010) The Spitzer c2d survey of weak-line T Tauri stars. III. The transition from primordial disks to debris disks. Astrophysical Journal, 724 (2). pp. 835-854. ISSN 1538-4357

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Abstract

We present 3.6 to 70 μm Spitzer photometry of 154 weak-line T Tauri stars (WTTSs) in the Chamaeleon, Lupus, Ophiuchus, and Taurus star formation regions, all of which are within 200 pc of the Sun. For a comparative study, we also include 33 classical T Tauri stars which are located in the same star-forming regions. Spitzer sensitivities allow us to robustly detect the photosphere in the IRAC bands (3.6 to 8 μm) and the 24 μm MIPS band. In the 70 μm MIPS band, we are able to detect dust emission brighter than roughly 40 times the photosphere. These observations represent the most sensitive WTTSs survey in the mid- to far-infrared to date and reveal the frequency of outer disks (r = 3-50 AU) around WTTSs. The 70 μm photometry for half the c2d WTTSs sample (the on-cloud objects), which were not included in the earlier papers in this series, those of Padgett et al. and Cieza et al., are presented here for the first time. We find a disk frequency of 19% for on-cloud WTTSs, but just 5% for off-cloud WTTSs, similar to the value reported in the earlier works. WTTSs exhibit spectral energy distributions that are quite diverse, spanning the range from optically thick to optically thin disks. Most disks become more tenuous than L disk/L * = 2 × 10–3 in 2 Myr and more tenuous than L disk/L * = 5 × 10–4 in 4 Myr.

Item Type:	Article
Publisher’s Statement:	© 2010 The American Astronomical Society. Published by IOP Publishing.
ID number or DOI:	10.1088/0004-637X/724/2/835
Keywords:	binary-systems; centaurus ob association; circumstellar disks; high-resolution spectroscopy; hubble-space-telescope; infrared: stars; interstellar clouds; low-mass stars; main-sequence stars; planetary systems; Protoplanetary disks; stars: pre-main sequence; sun-like stars; terrestrial planet formation
Subjects:	Q Science > QB Astronomy
NAU Depositing Author Academic Status:	Faculty/Staff
Department/Unit:	College of Engineering, Forestry, and Natural Science > Physics and Astronomy
Date Deposited:	30 Sep 2015 18:54
URI:	http://openknowledge.nau.edu/id/eprint/443

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