Context. Spatially resolved observations of circumstellar disks at millimeter wavelengths allow detailed comparison with theoretical models for the radial and vertical distribution of the material. Aims. We investigate the physical structure of the gas component of the disk around the pre-main-sequence star HD169142 and test the disk model derived from the spectral energy distribution. Methods. The 13CO and C18O J=2–1 line emission is observed from the disk with 1. ′ ′ 4 resolution using the Submillimeter Array. We adopt the disk physical structure derived from a model which fits the spectral energy distribution of HD169142. We obtain the full three-dimensional information on the CO emission with the aid of a molecular excitation and radiative transfer code. This information is used for the analysis of our observations and previous 12CO J=2–1 and 1.3 mm continuum data. Results. The spatially resolved 13CO and C18O emission shows a Keplerian velocity pattern The disk is seen at an inclination close to 13 ◦ from face-on. We conclude that the regions traced by different CO isotopologues are distinct in terms of their vertical location within the disk, their temperature and their column densities. With the given disk structure, we find that freeze-out is not efficient enough to remove a significant amount of CO from gas phase. Both observed lines match the model prediction both in flux and in the spatial structure of the emission. Therefore we use our data to derive the 13CO and C18O mass and consequently the 12CO mass using standard isotopic ratios
To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.