The Masses of Transition Circumstellar Disks: Observational Support for Photoevaporation Models

Abstract

We report deep Sub-Millimeter Array observations of 26 pre-main-sequence (PMS) stars with evolved inner disks. These observations measure the mass of the outer disk (r ~20-100 AU) across every stage of the dissipation of the inner disk (r < 10 AU) as determined by the IR spectral energy distributions (SEDs). We find that only targets with high mid-IR excesses are detected and have disk masses in the 1-5 M_Jup range, while most of our objects remain undetected to sensitivity levels of M_DISK ~0.2-1.5 M_Jup. To put these results in a more general context, we collected publicly available data to construct the optical to millimeter wavelength SEDs of over 120 additional PMS stars. We find that the near-IR and mid-IR emission remain optically thick in objects whose disk masses span 2 orders of magnitude (~0.5-50 M_Jup). Taken together, these results imply that, in general, inner disks start to dissipate only after the outer disk has been significantly depleted of mass. This provides strong support for photoevaporation being one of the dominant processes driving disk evolution.

Accepted for publication by ApJL, 4 pages and 3 figures

References in corpus (6)

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Cited by in corpus (4)

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• The Nature of Transition Circumstellar Disks II. Southern Molecular Clouds
• No Transition Disk? Infrared Excess, PAH, H2, and X-rays from the Weak-Lined T Tauri Star DoAr 21
• Circumstellar disks and planets. Science cases for next-generation optical/infrared long-baseline interferometers