Fractal aggregates in reduced gravity experiments and numerical simulations to characterize cometary material properties
In: 38th COSPAR Scientific Assembly ; https://hal.science/hal-00793212 ; 38th COSPAR Scientific Assembly, Jul 2010, Bremen, Germany, 2010
Konferenz
Zugriff:
In situ missions have shown that cometary dust particles have low densities and are easily fragmenting aggregates [1]. The linear polarization of the solar light scattered by cometary dust corresponds to bell-shaped (with a small negative branch and a maximum below 30%) phase curves with a quasi-linear increase with the wavelength between 30° and 50° phase angle [2]. Such physical properties of the cometary material are reconciled by a fractal model of cometary dust and comet nuclei as formed by aggregation in reduced gravity as studied by laboratory experiments and numerical simulations. Reduced gravity light scattering experiments: The CODAG-LSU experiment (1999) gave the first indication of the light scattering properties transition between single particles and low dimensions fractal aggregates (D 1.3) [3, 4]. Such studies will be pursued on board the ISS with the ICAPS precursor experiment. The PROGRA2 experiment is designed to study the light scattering properties of particles levitated during dedicated microgravity flights or with ground-based configurations [5]. The material properties are chosen so as to be relevant in the context of cosmic dust from cometary and asteroidal origins. It is especially useful to disentangle the effects of varying albedos of constitutive materials [6], shape and size of constitutive grains [7]. Some of the results are interpreted in terms of fractal aggregates growth. Light scattering numerical simulations Based on numerical simulations and in coherence with the experimental results, a model of cometary coma by a mixture of fractal aggregates of up to 256 sub-micron sized spheroidal grains and compact spheroidal particles is shown to reproduce the polarimetric observations of comets such as 1P/Halley or C/1995 O1 Hale-Bopp [8]. Physical parameters of the size distribution of particles (minimum and maximum size, shape of the size distribution and quantity and location of absorbing and non-absorbing particles) can be retrieved to determine cometary dust properties useful to ...
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Fractal aggregates in reduced gravity experiments and numerical simulations to characterize cometary material properties
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Autor/in / Beteiligte Person: | Lasue, Jérémie ; Levasseur-Regourd, Anny Chantal ; Hadamcik, Edith ; Botet, Robert ; Renard, Jean-Baptiste ; Lunar and Planetary Institute Houston (LPI) ; PLANETO -, LATMOS ; Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS) ; Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) ; Laboratoire de Physique des Solides (LPS) ; Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS) ; Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E) ; Observatoire des Sciences de l'Univers en région Centre (OSUC) ; Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris ; Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris ; Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales Paris (CNES) |
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Zeitschrift: | 38th COSPAR Scientific Assembly ; https://hal.science/hal-00793212 ; 38th COSPAR Scientific Assembly, Jul 2010, Bremen, Germany, 2010 |
Veröffentlichung: | HAL CCSD, 2010 |
Medientyp: | Konferenz |
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