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Methanol and hydrogen sulfide in comet P/Halley.

Eberhardt, P.; Meier, R.; Krankowsky, D. +1 more

The Neutral Mass Spectrometer on the Giotto spacecraft measured the gas and ion composition in the coma of comet P/Halley. A detailed model of the ion chemistry inside the contact surface located at 4660 km is used to interpret the measured ion density profiles in the 32 to 35 amu/e mass range. The masses 33 and 35 amu/e are dominated by the proto…

Ammonia in comet P/Halley.

Eberhardt, P.; Meier, R.; Krankowsky, D. +1 more

In comet P/Halley the abundances of ammonia relative to water reported in the literature differ by about one order of magnitude from roughly 0.1% up to 2%. Different observational techniques seem to have inherent systematic errors. Using the ion mass channels m/q=19amu/e, 18amu/e and 17amu/e of the Neutral Mass Spectrometer experiment aboard the s…

Abundance and origin of the CH_n_^+^ ions in the coma of comet P/Halley

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

We analyzed data in the mass/charge group 12-16 amu/e from the High Intensity Sensor (HIS) of the Ion Mass Spectrometer IMS on board the spacecraft Giotto during the comet Halley flyby. The most abundant ion in this mass/charge range is CH_3_^+^. Its parent molecules are either CH_2_, CH_3_ or CH_4_. Hereby, the methane abundance serves as an impo…

The radial brightness dependence in the dust coma of comet P/Grigg-Skjellerup.

Fulle, M.; Mennella, V.; Colangeli, L. +2 more

In a previous paper (Fulle et al. 1993a) we have obtained a three-dimensional coma model of the short period comet P/Grigg-Skjellerup, by fitting ground-based images taken in coincidence with the fly-by of the GIOTTO spacecraft (GEM mission). Concerning the cometary dust environment, we confirmed the excess of large grains measured by the in-situ …