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We report Submillimeter Array observations of SO2 emission in thecircumstellar envelope of the red supergiant VY CMa, with an angular resolutionof ~1". SO2 emission appears in three distinct outflow regions surrounding thecentral continuum peak emission that is spatially unresolved. No bipolarstructure is noted in the sources. A fourth source of SO2 is identified as aspherical wind centered at the systemic velocity. We estimate the SO2 columndensity and rotational temperature assuming local thermal equilibrium (LTE) aswell as perform non-LTE radiative transfer analysis using RADEX. Columndensities of SO2 are found to be ~10^16 cm^-2 in the outflows and in thespherical wind. Comparison with existing maps of the two parent species OH andSO shows the SO2 distribution to be consistent with that of OH. The abundanceratio f_SO2/f_SO is greater than unity for all radii greater than at least3x10^16 cm. SO2 is distributed in fragmented clumps compared to SO, PN, and SiSmolecules. These observations lend support to specific models of circumstellarchemistry that predict f_SO2/f_SO>1 and may suggest the role of localizedeffects such as shocks in the production of SO2 in the circumstellar envelope.

Arcsecond resolution mapping of Sulfur Dioxide emission in the circumstellar envelope of VY Canis Majoris