  We present Submillimeter Array observations of the Herbig Ae star HD169142 in
1.3 millimeter continuum emission and 12CO J=2-1 line emission at 1.5 arcsecond
resolution that reveal a circumstellar disk. The continuum emission is centered
on the star position and resolved, and provides a mass estimate of about 0.02
solar masses for the disk. The CO images show patterns in position and velocity
that are well matched by a disk in Keplerian rotation with low inclination to
the line-of-sight. We use radiative transfer calculations based on a flared,
passive disk model to constrain the disk parameters by comparison to the
spectral line emission. The derived disk radius is 235 AU, and the inclination
is 13 degrees. The model also necessitates modest depletion of the CO
molecules, similar to that found in Keplerian disks around T Tauri stars.
