Indications for grain growth and mass decrease in cold dust disks around Classical T Tauri stars in the MBM 12 young association

Abstract

We report detection of continuum emission at 850 and 450 micron from disks around four Classical T Tauri stars in the MBM 12 (L1457) young association. Using a simple model we infer masses of 0.0014-0.012 M_sun for the disk of LkHa 263 ABC, 0.005-0.021 M_sun for S18 ABab, 0.03-0.18 M_sun for LkHa 264 A, and 0.023-0.23 M_sun for LkHa 262. The disk mass found for LkHa 263 ABC is consistent with the 0.0018 M_sun inferred from the scattered light image of the edge-on disk around component C. Comparison to earlier 13CO line observations indicates CO depletion by up to a factor 300 with respect to dark-cloud values. The spectral energy distributions (SED) suggest grain growth, possibly to sizes of a few hundred micron, but our spatially unresolved data cannot rule out opacity as an explanation for the SED shape. Our observations show that these T Tauri stars are still surrounded by significant reservoirs of cold material at an age of 1-5 Myr. We conclude that the observed differences in disk mass are likely explained by binary separation affecting the initial value. With available accretion rate estimates we find that our data are consistent with theoretical expectations for viscously evolving disks having decreased their masses by ~30%.

15 pages, 3 figures, uses aastex. ApJ Letters, in press

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Cited by in corpus (10)

• Circumstellar Dust Disks in Taurus-Auriga: The Submillimeter Perspective
• Detecting the Dusty Debris of Terrestrial Planet Formation
• Evolution of Cold Circumstellar Dust Around Solar-Type Stars
• Attenuation of Millimeter Emission from Circumstellar Disks Induced by the Rapid Dust Accretion
• Keck Adaptive Optics Imaging of Nearby Young Stars: Detection of Close Multiple Systems
• Formation and Evolution of Planetary Systems: Upper Limits the Gas Mass in HD105
• MBM 12: young protoplanetary discs at high galactic latitude
• Constraints on Inner Disk Evolution Timescales: A Disk Census of the eta Chamaeleontis Young Cluster
• High spatial resolution optical imaging of the multiple T Tauri system LkHα 262/LkHα 263
• AzTEC 1.1 mm Observations of the MBM12 Molecular Cloud