title: HCO+ in the coma of comet Hale-Bopp.
abstract: Maps of comet C/1995 O1 (Hale-Bopp) in the millimeter-wave emission of the ion HCO+ revealed a local minimum near the nucleus position, with a maximum about 100,000 km in the antisolar direction. These observed features of the HCO+ emission require a low abundance of HCO+ due to enhanced destruction in the inner coma of the comet, within a region of low electron temperature (Te). To set constraints on the formation of HCO+ in the coma, as well as the location and magnitude of the transition to higher Te, the data are compared with the results of ion-molecule chemistry models.
authors.affiliation: Five College Radio Astronomy Observatory, University of Massachusetts, Amherst 01003, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Lovell
authors.forename: F P
authors.initials: FP
authors.lastname: Schloerb
authors.forename: E A
authors.initials: EA
authors.lastname: Bergin
authors.forename: J E
authors.initials: JE
authors.lastname: Dickens
authors.forename: C H
authors.initials: CH
authors.lastname: Devries
authors.forename: M C
authors.initials: MC
authors.lastname: Senay
authors.forename: W M
authors.initials: WM
authors.lastname: Irvine
mesh_terms: D055580:Astronomical Phenomena; D001256:Astronomy; D005118:Extraterrestrial Environment; D006838:Hydrocarbons / Q000032:analysis*; D007477:Ions; D019110:Meteoroids; D010777:Photochemistry; D013057:Spectrum Analysis
chemical_list: D006838:Hydrocarbons; D007477:Ions