Spatial distribution of neutral and ionic constituents in comet P/Halley

Abstract

Abstract. Multislit spectra of comet P/Halley were obtained on April 10, 1986, using a focal reducer with a field of ≈ 0.5• 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 4 10 5 × 4 10 5 km 2 at the comet. Radial profiles and two-dimensional maps for the dust continuum, CN, C 3 , CH, CO + , and especially CO + 2 , 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 CO + 2 shows a stronger decrease in the tailward direction than that of CO + .

The optical spectra of comets

“…Так, типи речовини iонiв часто називають типами речовини хвоста. Проте, необхiдно вiдмiтити, що багато iонiв спостерiгаються вiдносно близько вiд ядра комети (гарною iлюстрацiєю є отриманi з довгою щiлиною спектри CO + i CO + 2 в кометi 1Р/Галлея [97]). Домiнуючими процесами для утворення iонiв є фотодисоцiацiя (наприклад, H 2 O+hν → OH + + H+e) i фотоiонiзацiя (наприклад, H 2 O + hν → H 2 O + + e) [98].…”

Absolute yields of CO(a′ 3Σ+, d 3Δi,e 3Σ−)+O from the dissociative recombination of CO2+ ions with electrons

“…11 Results from the neutral mass spectrometer experiment onboard the Giotto spacecraft demonstrated that CO was produced by a distributed source near the nucleus rather than directly from the nucleus. 11 Results from the neutral mass spectrometer experiment onboard the Giotto spacecraft demonstrated that CO was produced by a distributed source near the nucleus rather than directly from the nucleus.…”