2005AJ....130..261M

I present results from a sensitive imaging search for CH₃OH and C₂H in two oxygen-rich stars (IK Taurus and TX Camelopardalis) carried out with the Owens Valley Millimeter Array. Neither CH₃OH nor C₂H are detected in these stars, in agreement with single-dish observations by Charnley and Latter. The observations place upper limits on the fractional abundance of C₂H of 9.7x10^–9 in IK Tau and 3.2x10^–8 in TX Cam and also place upper limits on the fractional abundance of CH₃OH of 4.5x10^–9 in IK Tau and 1.1x10^–8 in TX Cam. A chemical model developed by Charnley and coworkers explaining the presence of HCN in these objects is clearly ruled out by these observations. The HCN distribution in these oxygen-rich stars has been mapped with a resolution of ~3". The HCN emission is marginally resolved, centrally concentrated, and does not appear to be well fitted by a thin-shell model. Continuum fluxes for the sources have been measured. At 96.7 GHz, the observed continuum fluxes were 6.1±0.4 mJy for IK Tau and 3.7±0.4 mJy for TX Cam. The continuum emission is unresolved at the ~3" level, as expected from a model for the emission mechanism proposed by Reid and Menten.