  We present 7mm observations of the dusty disk surrounding the 10 Myr old 1.5
Msun pre-main-sequence star CQ Tauri obtained at the Very Large Array with 0.8
arcsecond resolution and 0.1 mJy rms sensitivity. These observations resolve
the 7mm emission in approximately the north-south direction, confirming
previous results obtained with lower resolution. We use a two-layer flared disk
model to interpret the observed fluxes from 7mm to 1.3mm together with the
resolved 7mm structure. We find that the disk radius is constrained to the
range 100 to 300 AU, depending on the steepness of the disk surface density
distribution. The power law index of the dust opacity coefficient, beta, is
constrained to be 0.5 to 0.7. Since the models indicate that the disk is
optically thin at millimeter wavelengths for radii greater than 8 AU, the
contribution of an optically thick region to the emission is less than 10%.
This implies that high optical depth or complex disk geometry cannot be the
cause of the observed shallow millimeter spectral index. Instead, the new
analysis supports the earlier suggestion that dust particles in the disk have
grown to sizes as large as a few centimeters. The dust in the CQ Tauri system
appears to be evolved much like that in the TW Hydra system, a well-studied
pre-main-sequence star of similar age and lower mass. The survival of gas-rich
disks with incomplete grain evolution at such old ages deserves further
investigations.
