The Distribution, Excitation, and Formation of Cometary Molecules: Methanol, Methyl Cyanide, and Ethylene Glycol

We present an interferometric and single-dish study of small organic species toward Comets C/1995 O1 (Hale-Bopp) and C/2002 T7 (LINEAR) using the BIMA interferometer at 3 mm and the ARO 12 m telescope at 2 mm. For Comet Hale-Bopp, both the single-dish and interferometer observations of CH sub(3)OH indicate an excitation temperature of [image] K and an average production rate ratio [image] at [image]1 AU. In addition, the aperture synthesis observations of CH sub(3)OH suggest a distribution well described by a spherical outflow and no evidence of significant extended emission. Single- dish observations of CH sub(3)CN in Comet Hale-Bopp indicate an excitation temperature of [image] K and a production rate ratio of [image] at [image]1 AU. The nondetection of a previously claimed transition of cometary (CH sub(2)OH) sub(2) toward Comet Hale-Bopp with the 12 m telescope indicates a compact distribution of emission, [image] (