A&A Supplement series, Vol. 127, February I 1998, 479-495
Received September 6, 1996; accepted April 30, 1997
R. Umbach, - K. Jockers - E.H. Geyer
Send offprint request: K. Jockers
Max-Planck-Institut für Aeronomie, Postfach 20, 37189 Katlenburg-Lindau, Germany
Sternwarte der Universität Bonn, Observatorium Hoher List, 54550 Daun, Germany
Multislit spectra of comet P/Halley were obtained on April 10, 1986, using a focal reducer with a field of angular diameter. The number and arrangement of the slits allowed a reconstruction of the spatial distribution of principal neutral and ionic coma constituents within a frame of about at the comet. Radial profiles and two-dimensional maps for the dust continuum, CN, , CH, , and especially , are presented in absolute intensity and column density units, respectively. Scale lengths and production rates for the radicals were determined within the Haser model. The molecular ions are not only restricted to the plasma tail but are also present in the sunward coma. Instead of forming a peak at the nucleus like the neutral radicals the ion column densities decrease rapidly in the solar direction and form a plateau extending from the nucleus into the antisolar direction. The distribution of shows a stronger decrease in the tailward direction than that of .
keywords: comets: individual: P/Halley -- multislit spectra -- molecular ions -- radicals -- spatial distribution