Imaging the Disk around TW Hya with the SMA
          Chunhua Qi, CfA
          David Wilner, CfA
          Nuria Calvet, CfA
          Paul Ho, CfA
          Nuria Calvet, CfA
          Geoffrey Blake, Caltech
          Michiel Hogerheijde, Sterrewacht Leiden

          We present 2-4 arcsecs aperture synthesis observations of the circumstellar disk surrounding the nearby young star TW Hya in the CO J=2-1 and J=3-2 lines and associated dust continuum obtained with the Submillimeter Array. Rigorous comparisons of the molecular images with 2D Monte Carlo models have been used to constrain the global disk properties including the inclination angle, disk radius etc., using the Chi-square analysis within the visibility domain. Substantial CO depletion and higher gas temperature vs dust temperature are required to explain the line emission. Such analysis should serve as a robust tool for investigating the temperature and chemical structure of the TW Hya disk.