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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…
The Organic Matter of Comet Halley as Inferred by Joint Gas Phase and Solid Phase Analyses
Korth, A.; Kissel, J.; Krueger, F. R.
During encounters with comet Halley, the experiment PICCA onboard GIOTTO measured the gas phase organic ion composition of the coma and the experiment PUMA onboard VEGA-1 measured the dust composition. Joining both results, we obtain a consistent picture of the parent organic matter from which dust and gas is produced. One recognizes a complex uns…
A Note on the Statistical Evaluation of Compressed Mass Spectra Obtained from Dust Particles in the Coma of Comet Halley
Jessberger, E. K.; Fomenkova, M.; Mukhin, L. +4 more
A weighing factor for individual dust grains based on an independent determination of the particle mass (rather than summing up the total number of ions of an element measured in all spectra) is established for the calculation of the average dust composition. The ion ratio distribution obtained from particles with different masses independent of c…
The Comet Halley Dust and Gas Environment
Keller, H. U.; Gombosi, T. I.; Sekanina, Z. +8 more
Quantitative descriptions of environments near the nucleus of comet P/Halley have been developed to support spacecraft and mission design for the flyby encounters in March, 1986. To summarize these models as they exist just before the encounters, we review the relevant data from prior Halley apparitions and from recent cometary research. Orbital e…