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The extended formaldehyde source in comet P/Halley

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

The Neutral Mass Spectrometer on the Giotto spacecraft measured the neutral and ion composition in the coma of comet P/Halley. In the ion mass spectra, the 31 amu/e peak is dominated by the protonated formaldehyde ion H₃CO⁺ and can be used to calculate the H₂CO density. The radial profile of the amplitude of the 31…

First results from the Giotto magnetometer experiment during the P/Grigg-Skjellerup encounter

Glassmeier, K. -H.; Neubauer, F. M.; Pohl, M. +9 more

The Giotto magnetic field experiment has provided the first magnetic field data on the interaction between the solar wind and a low gas production comet, P/Grigg-Skjellerup. Waves produced by ion pick-up instabilities have been observed throughout the interaction region with particularly simple waveforms at large distances and a rich phenomenology…

Observations of the Solar Wind and Cometary Ions during the Encounter Between Giotto and Comet Grigg-Skjellerup

Coates, A. J.; Winningham, J. D.; Borg, H. +6 more

The solar wind interaction with the outfiowing gas from a second comet has been recorded by the same in-situ instrumentation that was used for the comet Halley encounter m 1986. The new comet, Grigg-Skjellerup, is the smallest so far observed since the size of the interaction region is comparable with a cometary ion gyroradius Preliminary results …

The ion population between 1300 KM and 230000 KM in the coma of comet P/Halley

Altwegg, K.; Balsiger, H.; Geiss, J. +6 more

During the encounter of the spacecraft Giotto with Comet Halley the two sensors of the ion mass spectrometer (IMS), high energy range spectrometer (HERS) and high intensity spectrometer (HIS), measured the mass and the three-dimensional velocity distributions of cometary ions. HIS looked mainly at the cold, slow part of the distribution close to t…