DPS Pasadena Meeting 2000, 23-27 October 2000
Session 41. Comets Posters - Coma, Tails, Solar Wind Interaction
Displayed, 1:00pm, Monday - 1:00pm, Friday, Highlighted Tuesday and Thursday, 3:30-6:30pm, C101-C105, C211

## [41.04] The Production of O({1}D) in Comet Hale-Bopp

J. P. Morgenthaler, W. Harris, F. Scherb, C. M. Anderson, N. E. Doane, F. L. Roesler (UW--Madison), R. J. Oliversen (GSFC), M. R. Combi (University of Michigan)

Photometric observations of comet Hale-Bopp (C/1995 OI) in the forbidden red line of neutral oxygen ([O~I]~6300~Å) with three independent telescopes on Kitt Peak in March of 1997 imply a production rate of the metastable O({1}D) of 300--400\times1028 s-1. Using water production rates determined by Combi et al. (2000), and the standard water and OH photodissociation branching ratios found in Hübner et al. (1992) and Van Dishoeck and Dalgarno (1984), we expect 88 \times 1028 s-1. We explore several hypotheses that would account for this discrepancy, including: (1) the branching ratio of OH to O({1}D) is incorrect, (2) the photodissociation of other species, such as CO and CO2 contribute significantly to O({1}D) production, and (3) ground state oxygen is excited to the metastable level by collisional processes.

This work has been supported under NSF grant AST-9615625 and NASA grant NAG~5-7952.