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Comet Halley's Gas Composition and Extended Sources: Results from the Neutral Mass Spectrometer on Giotto

Eberhardt, Peter

The Neutral Mass Spectrometer on the Giotto spacecraft established that H₂O is the dominant species in Comet Halley's volatiles and determined the abundance of more than 10 parent species. The instrument discovered strong extended H₂CO and CO sources in the coma of Comet Halley. Polymerized H₂CO associated with the…

Polarization of Light Scattered by Cometary Dust Particles: Observations and Tentative Interpretations

Levasseur-Regourd, A. -Chantal

Analysis of the polarization of light scattered by cometary particles reveals similarities amongst the phase curves, together with some clear differences: i) comets with a strong silicate emission feature present a high maximum in polarization, ii) the polarization is always slightly lower than the average in inner comae and stronger in jet-like s…

Composition of the Volatile Material in Halley's Coma from In Situ Measurements

Altwegg, K.; Balsiger, H.; Geiss, J.

The investigation of the volatile material in the coma of comets is a key to understanding the origin of cometary material, the physical and chemical conditions in the early solar system, the process of comet formation, and the changes that comets have undergone during the last 4.6 billion years. So far, in situ investigations of the volatile cons…

Review, based on particles and fields observations made aboard the Giotto spacecraft, concerning the nature of the solar wind interaction with comets P/Halley and P/Grigg Skjellerup

McKenna-Lawlor, Susan M. P.

A key driver underlying the decision to command the Giotto spacecraft on to an encounter with comet P/Grigg-Skjellerup following its highly successful encounter with P/Halley, was the unique scientific opportunity this provided to compare measurements made using the same suite of plasma and fields instruments at (a) very active and 'fresh' comet P…