Search Publications
Molecular Oxygen in Oort Cloud Comet 1P/Halley
Altwegg, K.; Rubin, M.; van Dishoeck, E. F. +1 more
Recently, the ROSINA mass spectrometer suite on board the European Space Agency's Rosetta spacecraft discovered an abundant amount of molecular oxygen, O2, in the coma of Jupiter family comet 67P/Churyumov-Gerasimenko of O2/H2O = 3.80 ± 0.85%. It could be shown that O2 is indeed a parent species and that…
Dusty Plasma Effects in Comets: Expectations for Rosetta
Mendis, D. A.; Horányi, M.
Despite their small masses, comets have played an extraordinary role in enhancing our understanding of cosmic physics. It was the calculation of comet Halley's orbit and the successful prediction of its return in 1758 that firmly established the correctness of Newton's law of universal gravitation. It was the morphology of the dusty tails of comet…
The Chemical Composition of Comets—Emerging Taxonomies and Natal Heritage
Mumma, Michael J.; Charnley, Steven B.
Cometary nuclei contain the least modified material from the formative epoch of our planetary system, and their compositions reflect a range of processes experienced by material prior to its incorporation in the cometary nucleus. Dynamical models suggest that icy bodies in the main cometary reservoirs (Kuiper Belt, Oort Cloud) formed in a range of…
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…
Optical properties of dust from Jupiter family comets
Levasseur-Regourd, A. C.; Hadamcik, E.
To try to define specific physical properties of the dust of Jupiter-family comets (JFCs), we compare the light scattered by them. Amongst the more than 1000 JFCs, less than 200 are numbered, 40 of them being rather bright. In the present work we use data from the latter. In situ observations of three nuclei show low albedo surfaces. The albedo of…
Probing the internal structure of the nuclei of comets
Lasue, J.; Levasseur-Regourd, A. C.; Hadamcik, E. +1 more
There is no direct evidence about the internal structure of cometary nuclei, which are mostly hidden by their gas and dust comae, and have not yet been orbited by any spacecraft. Their densities are low, typically of about 400 kg m -3 for 9P/Tempel 1 (that was impacted by the Deep Impact probe) and 67P/Churyumov-Gerasimenko (that is the…
Physical properties of cometary and interplanetary dust
Lasue, J.; Okada, Y.; Mukai, T. +1 more
In the absence of numerous in situ studies, physical properties of cosmic dust may be derived from observations of their light scattering and thermal properties, through numerical simulations making use of realistic assumptions. Estimations about cometary and interplanetary dust composition, structure, size, as well as about their light scattering…
Comparison of the dust distributions in the innermost comae of comets—1P/Halley and 19P/Borrelly spacecraft observations
Thomas, Nicolas; Tenishev, Valeriy; Combi, Michael +3 more
We present a comparative study of the inner comae of comets 1P/Halley and 19P/Borrelly using data from the Halley Multicolour Camera (HMC) onboard Giotto and the Miniature Integrated Camera and Spectrometer onboard Deep Space 1 (DS1). We show that the dust brightness dependence as a function of radial distance is different for both comets. We sugg…