The Herschel DIGIT Survey of Weak-line T Tauri Stars: implications for disk evolution and dissipation

Abstract

As part of the "Dust, Ice, and Gas In Time (DIGIT)" Herschel Open Time Key Program, we present Herschel photometry (at 70, 160, 250, 350 and 500 micron) of 31 Weak-Line T Tauri star (WTTS) candidates in order to investigate the evolutionary status of their circumstellar disks. Thirteen stars in our sample had circumstellar disks previously known from infrared observations at shorter wavelengths, while eighteen of them had no previous evidence for a disk. We detect a total of 15 disks as all previously known disks are detected at one or more Herschel wavelengths and two additional disks are identified for the first time. The spectral energy distributions (SEDs) of our targets seem to trace the dissipation of the primordial disk and the transition to the debris disk regime. Seven of the 15 disks appear to be optically thick primordial disks, including two objects with SEDs indistinguishable from those of typical Classical T Tauri stars, four objects that have significant deficit of excess emission at all IR wavelengths, and one "pre-transitional" object with a known gap in the disk. Despite their previous WTTS classification, we find that the seven targets in our sample with optically thick disks show evidence for accretion. The remaining eight disks have weaker IR excesses similar to those of optically thin debris disks. Six of them are warm and show significant 24 micron Spitzer excesses, while the last two are newly identified cold debris-like disks with photospheric 24 micron fluxes, but significant excess emission at longer wavelengths. The Herschel photometry also places strong constraints on the non-detections, where systems with F70/F70,star > 5 - 15 and L,disk/L,star > 1xE-3 to 1xE-4 can be ruled out. We present preliminary models for both the optically thick and optically thin disks and discuss our results in the context of the evolution and dissipation of circumstellar disks.

Accepted for publication in ApJ

References in corpus (19)

• Coagulation, fragmentation and radial motion of solid particles in protoplanetary disks
• Photoevaporation of protoplanetary discs II: evolutionary models and observable properties
• A Submillimeter View of Circumstellar Dust Disks in $\rho$ Ophiuchus
• Search for Associations Containing Young stars (SACY): I. Sample & Searching Method
• Debris disks around Sun-like stars
• On the Diversity of the Taurus Transitional Disks: UX Tau A & Lk Ca 15
• Variations on Debris Disks: Icy Planet Formation at 30-150 AU for 1-3 Solar Mass Main Sequence Stars
• A VLT/NACO Survey for Triple and Quadruple Systems among Visual Pre-Main Sequence Binaries
• New periodic variable stars coincident with ROSAT sources discovered using SuperWASP
• Accretion Disks around Young Stars: Lifetimes, Disk Locking and Variability
• Investigating grain growth in disks around southern T Tauri stars at millimetre wavelengths
• A Herschel Survey of Cold Dust in Disks Around Brown Dwarfs and Low-Mass Stars
• 870 micron Imaging of a Transitional Disk in Upper Scorpius: Holdover from the Era of Giant Planet Formation?
• The Masses of Transition Circumstellar Disks: Observational Support for Photoevaporation Models
• Spitzer observations of the Hyades: Circumstellar debris disks at 625 Myr of age
• A Survey for Young Spectroscopic Binary K7-M4 Stars in Ophiuchus
• Mass and Temperature of the TWA 7 Debris Disk
• No Transition Disk? Infrared Excess, PAH, H2, and X-rays from the Weak-Lined T Tauri Star DoAr 21
• Submillimeter Array Observations of the RX J1633.9-2442 Transition Disk: Evidence for Multiple Planets in the Making

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