Search Publications
Dust particle impacts during the Giotto encounter with comet Grigg-Skjellerup
Colangeli, L.; Green, S. F.; Greenberg, J. M. +7 more
IN the European Space Agency's 1992 Giotto Extended Mission, the Dust Impact Detection System operated successfully during a fly-by that took the spacecraft within about 200 km of the nucleus of comet Grigg-Skjellerup. During the encounter, three meteoroid impacts were detected on Giotto's front shield. The particle masses were found to be lOO
Negative ions in the coma of comet Halley
Chaizy, P.; Anderson, K. A.; Reme, H. +8 more
IN March 1986, the Giotto spacecraft encountered comet Halley, approaching to within ~600 km of the nucleus. Results from this encounter have shown that the inner coma contains a mixture of cometary neutral gas and dust, thermal ions and electrons, fast cometary pick-up ions, and decelerated solar-wind ions and electrons, as well as fast neutrals<…
Probable detection of organic-dust-borne aromatic C3H3+ ions in the coma of comet Halley
Anderson, K. A.; Reme, H.; Korth, A. +9 more
The heavy-ion analyser PICCA1,2 on the Giotto spacecraft was used to determine the composition and energy distribution of positively charged ions in the coma of comet Halley. Here we argue that the distinct peak observed at mass 39 AMU is due to the aromatic cation C3H3+ (cyclopropenyl). Laboratory mass …
Aspects of the major element composition of Halley's dust
Kissel, J.; Jessberger, E. K.; Christoforidis, A.
The chemical composition of the solid grains from comet Halley can be inferred from impact-ionization time-of-flight mass spectrometry. Halley's dust in the vicinity of the VEGA-1 spacecraft is a mixture of a refractory organic component and unequilibrated silicates, but detailed chemical information on individual particles is difficult to extract…
On the rotation axis of comet Halley
Keller, H. U.; Thomas, N.
The observations of comet Halley by the Halley Multicolour Camera (HMC) on board the European Space Agency's Giotto spacecraft were supported by an extensive ground-based observational programme using the same filter set1. The intention was to place the transitory but detailed observations of the encounter in the frame of ground-based o…
Giotto measurements of cometary and solar wind plasma at the Comet Halley bow shock
Coates, A. J.; Winningham, J. D.; Anderson, K. A. +19 more
The interaction of comets with the solar wind depends on the ionization of the heavy cometary neutrals (mostly H2O and its dissociation products O, OH) which flow out from the nucleus, and the coupling of these newly produced cometary ions with the solar wind through its embedded magnetic field. The 'pick-up' of these heavy ions slows t…
In situ gas and ion measurements at comet Halley
Berthelier, J. J.; Eberhardt, P.; Krankowsky, D. +9 more
The neutral mass spectrometer experiment (NMS) carried by the Giotto spacecraft was designed to determine the abundances and the chemical, elemental and isotopic composition of the gases and low-energy ions in the coma of comet Halley. Its first results show the predominance of water vapour (~80% by volume). Preliminary evaluation of the data yiel…
Ion composition and dynamics at comet Halley
Schwenn, R.; Altwegg, K.; Balsiger, H. +16 more
The ion mass spectrometer aboard the Giotto spacecraft measured the composition and velocity distributions of cometary ions at distances of ~7.5×l06 to ~1,300 km from the nucleus of comet Halley. Well outside the bow shock, pick-up cometary H+ ions were found in a diffuse shell-like distribution. Heavier ions (C+, …
First results from the Giotto magnetometer experiment at comet Halley
Neubauer, F. M.; Glassmeier, K. H.; Pohl, M. +9 more
The Giotto magnetometer experiment at comet Halley has for the first time provided magnetic field measurements in all the important spatial regions characterizing the front-side interaction between the solar-wind magnetoplasma and a cometary atmosphere. Upstream waves of cometary origin have been observed at distances of >2×106 km fr…
First Halley Multicolour Camera imaging results from Giotto
Wilhelm, K.; Keller, H. U.; Barbieri, C. +15 more
The first imaging results from the Halley Multicolour Camera (HMC) during the Giotto fly-by of comet Halley provide images centred on the brightest part of the inner coma which show the silhouette of a large, solid and irregularly shaped cometary nucleus and jet-like dust activity visible in reflected sunlight. A first assessment of the data yield…