Search Publications
Monte Carlo modeling of neutral gas and dust in the coma of Comet 1P/Halley
Hansen, Kenneth C.; Gombosi, Tamas I.; Combi, Michael R. +4 more
The neutral gas environment of a comet is largely influenced by dissociation of parent molecules created at the surface of the comet and collisions of all the involved species. We compare the results from a kinetic model of the neutral cometary environment with measurements from the Neutral Mass Spectrometer and the Dust Impact Detection System on…
Cometary dust properties retrieved from polarization observations: Application to C/1995 O1 Hale Bopp and 1P/Halley
Lasue, J.; Levasseur-Regourd, A. C.; Hadamcik, E. +1 more
The analysis of the polarized light scattered by cometary dust particles provides information on the physical properties of the solid component of cometary comae for C/1995 O1 Hale-Bopp and 1P/Halley. A model of light scattering by a size distribution of aggregates of up to 256 submicron-sized grains (spherical or spheroidal) mixed with single sph…
Ion composition and chemistry in the coma of Comet 1P/Halley—A comparison between Giotto's Ion Mass Spectrometer and our ion-chemical network
Hansen, Kenneth C.; Gombosi, Tamas I.; Combi, Michael R. +3 more
In order to understand the cometary plasma environment it is important to track the closely linked chemical reactions that dominate ion evolution. We used a coupled MHD ion-chemistry model to analyze previously unpublished Giotto High Intensity Ion Mass Spectrometer (HIS-IMS) data. In this way we study the major species, but we also try to match s…
Dust Grains in the Comae and Tails of Sungrazing Comets: Modeling of Their Mineralogical and Morphological Properties
Kimura, Hiroshi; Mann, Ingrid; Jessberger, Elmar K. +1 more
Observations of sungrazing comets, all of which belong to the Kreutz family, provide the opportunity of studying the properties of dust in the comae and tails of the comets. On the basis of available information on cometary and interplanetary dust as well as observations of dust in the tails of sungrazers, we model dust in sungrazing comets as flu…
The Dependence of the Circumnuclear Coma Structure on the Properties of the Nucleus
Rodionov, A. V.; Crifo, J. F.
A new step of development of the 3-D circumnuclear coma (“CNC”) model described in Crifoet al.(1995) is presented: now the gas and dust production are computed from an explicit dusty-ice sublimation model and a realistic dust mass spectrum is used. For the first time, (1) a clear distinction is made betweennucleus active area fraction gandactive s…
Cometary dust trails I. Survey
Sykes, Mark V.; Walker, Russell G.
Cometary dust trails were first observed by the Infrared Astronomical Satellite and consist of large refractory particles ejected from short-period comets at low velocities. Consequently, they tend to be found near the orbital paths of their parent bodies, their long and narrow appearance reminescent of airplane contrails. An examination of the en…
0.7- to 23-µm photometric observations of P/Halley 1986 III and six recent bright comets
Gehrz, R. D.; Ney, E. P.
We report 0.7- to 23-µm observations of P/Halley 1986 III and six other recent bright comets. P/Halley was measured on 47 occasions between 1985 December 12 UT and 1986 May 6 UT, several times within hours of the perihelion passage on 1986 February 9 UT. Our data show that the strength of the 10-µm silicate emission feature and the tem…
The origin of complex organic ions in the coma of Comet Halley
Reme, H.; Korth, A.; Lin, R. P. +3 more
Heavy ion mass spectra were obtained in the inner coma of Comet Halley by the Giotto-PICCA instrument. Outside the cometary ionopause, where ≳2000 K ion temperatures limited the effective mass resolution to 3 amu, the spectra exhibit a series of distinct mass groups that are separated by a constant ≈ 15 amu and extend to at least 120 amu. We show …
Modeling of the thermal behavior and of the chemical differentiation of cometary nuclei
Schmitt, B.; Espinasse, S.; Klinger, J. +1 more
Taking into account the low values of average density reported for Comet P/Halley, a model of a porous comet nucleus has been developed. The model includes heat conduction through the solid matrix and heat and mass transfers due to the vapor phase circulating in the pore system. Sublimation and recondensation of volatile species within the nucleus…
Large dust particles along the Giotto trajectory
Keller, H. U.; Curdt, W.
Images of Comet Halley taken by the Halley Multicolour Camera (HMC) onboard ESA's Giotto spacecraft provide highly accurate information on the viewing direction. As a part of the spacecraft dynamical system, HMC was very sensitive to attitude variations that occurred during the final approach phase. HMC identified several discrete events that were…