Masses of evolved disks in PMS stars

These observations measure the mass of the outer disk (r~20-100AU) across every stage of the dissipation of the inner disk (r<10AU) 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 1-5M_Jup_ range, while most of our objects remain undetected to sensitivity levels of M_DISK_~0.2-1.5M_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 emissions remain optically thick in objects whose disk masses span 2 orders of magnitude (~0.5-50M_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.