The European Hale-Bopp Team Observations of Comet Hale-Bopp

G. Cremonese (Obs. Padova), C. Arpigny, J. Manfroid (Ins.Astrop. Liege), D. Bockelee-Morvan, J. Crovisier, H. Rauer (Obs. Meudon), H. Boehnhardt (Ins.Astron. Munich), A. Fitzsimmons (Queens Univ. Belfast), M. Fulle (Obs. Trieste), K. Jockers, L. Jorda, N. Thomas (MPAE), H.-U. Kaufl, R. West (ESO), M. Kidger (IAC), P.-O. Lagage (CEA Saclay), H. Rickman (Obs. Uppsala), R. Schulz (ESA), G.-P. Tozzi (Obs. Firenze)

The poster reports some preliminary results obtained by the the European HB Team during an observational campaign, carried out with a substantial number of telescopes on the Canary Islands within a programme supported by the European Union. The observations were devoted to a variety of spectroscopic and photometric topics and have already provided important results. A highlight of this work was the discovery of a third tail composed of neutral sodium and the detection of substabtial amount of sodium in the dust tail. Potassium was found in the nuclear region and it was possible to obtain good definition of the rotation state of the comet nucleus. Other results are expected from the analysis of high resolution spectra, for instance the carbon isotopic ratio, the relative abundance of some ions in the coma, and of the very large collection of images from different telescopes with which the complex jet structure of the near nucleus region was monitored.