Comet Hale-Bopp, Fiber Optically Multiplexed, Medium Resolution Imaging Spectroscopy

C. M. Anderson (Dept. of Astronomy, U. Wisc-Madison), F. Scherb, F.L. Roesler (Dept. of Physics, U.Wisc-Madison)

The WIYN 3.5-meter telescope and its Multi-Object [Bench] Spectrograph have been used to obtain simultaneous spectra at many points in the coma of Comet Hale-Bopp. Between 1996 October and 1997 April in excess of 7500 individual spectra were obtained. On six nights the "Hydra" fiber positioner was used to sample a ring pattern of 96 points about the nucleus with a minimum spacing of 40 arc seconds and a maximum radius of 22.5 arc minutes. On four nights a new "Densepak" fiber cable was used. In this configuration a 7 x 13 rectangular pattern of 91 fibers on 4 arc second centers was used. In both casese the individual fibers are 3 arc seconds in diameter. In most cases the bench spectrograph was used in the echelle configuration with an interference filter to isolate a single order. The wavelength range tex2html_wrap_inline15 tex2html_wrap_inline15 6100 - 6400 Å was recorded with resolution tex2html_wrap_inline19 . This spectral region contains the emission features of [O I], tex2html_wrap_inline21 and tex2html_wrap_inline23 . . From this mass of data we are beginning to extract the radial, azimuthal and temporal variations of many different spectral features. For instance, the radial profile of [OI] tex2html_wrap_inline15 6300 Å intensity shows evidence of quenching of the metastable singlet-D state, radial acceleration or both. We expect to have subjected some of these diagnostic indices to preliminary modeling analysis and will display these results.

This research is supported by NSF grant AST - 9615625.