Search Publications
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…
Similarities between in situ measurements of local dust light scattering and dust flux impact data within the coma of 1P/Halley
Fulle, M.; Levasseur-Regourd, A. C.; McBride, N. +1 more
In situ measurements of the light locally scattered by cometary dust, as well as the local dust spatial density are only available for one comet, 1P/Halley. These data, returned from the Optical Probe Experiment (OPE) and the Dust Impact Detection System (DIDSY) aboard the European Space Agency spacecraft Giotto, are re-assessed in light of the re…
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…
Numerical simulation of the dust flux on a spacecraft in orbit around an aspherical cometary nucleus - I
Fulle, M.; Rodionov, A. V.; Crifo, J. F.
This study is the first investigation of the dust collection by a spacecraft orbiting a cometary nucleus, which is based on a physically consistent ab-initio model of the dust distribution in the vicinity of an aspherical comet nucleus. The homogeneous bean-shaped nucleus of Crifo & Rodionov (1997a) is used, with updated parameter values adapt…
The induced magnetosphere of comet Halley 4. Comparison of in situ observations and numerical simulations
Neubauer, F. M.; Gombosi, T. I.; Israelevich, P. L. +3 more
A comprehensive comparison between the results of a multiscale three-dimensional adaptive MHD model of the comet Halley magnetosphere and in situ observations by the Giotto mission is presented. It is shown how a steady state model can describe the effects of the varying IMF direction on the cometary magnetosphere. The simulation results reproduce…
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…
A flux enhancement measured in energetic particles(E ∼ 60-100 keV) by the epona instrument aboard Giotto close to P⧸Grigg-Skjellerup, and its interpretationas the signature of a companion comet
McKenna-Lawlor, Susan M. P.; Afonin, Valerie V.
A significant flux enhancement in energetic particles (E ∼ 60-⩾260 keV),showing internal fine structure interpreted to represent signatures produced during the traversalof various cometary boundaries in P⧸Grigg-Skjellerup, was recorded by the EPONA instrumentaboard spacecraft Giotto on 10 July 1992. A further internally structured flux enhancement…