Session 8 - Planets and Comets.
Display session, Monday, June 08
Atlas Ballroom,

## [8.03] BIMA Array Observations of Comet Hale-Bopp: Evidence of Deviations from Spherical Outflow

J. M. Veal, L. E. Snyder (U. Illinois), I. de Pater, M. C. H. Wright, J. R. Forster (UC Berkeley), P. Palmer (U. Chicago), L. M. Woodney, M. F. A'Hearn (U. Maryland), Y. -J. Kuan (ASIAA, Taiwan)

Interferometric observations of Comet Hale-Bopp were conducted with the Berkeley-Illinois-Maryland Association (BIMA) millimeter array in March and April of 1997. Nine antennas were used to detect HCN J=1\rightarrow0 emission at 88.6 GHz with approximate angular resolution of 9^\prime\prime. Prior to comet Hale-Bopp, spectral line detections at millimeter wavelengths were restricted to single element telescopes. Consequently, this comet is the first to be imaged with relatively high resolution at 3 mm. We have examined several days of HCN maps in order to explore the deviation of the detected emission from that expected for a spherically symmetric nuclear source. To this end, we have created model images to represent what would have been mapped had the comet actually been a spherically symmetric nuclear source. These model images were then subtracted from the corresponding observed images, resulting in a set of HCN difference maps''. These difference maps are displayed and their structures discussed.