HYDROCODE SIMULATIONS OF AGGREGATE DUST PARTICLE IMPACTS ONTO STARDUST Al FOILS
نویسندگان
چکیده
Introduction: We have used the Ansys Inc. AUTODYN ® software [1] to hydrodynamically model small particle impacts into aluminium (Al) foil, under the conditions of the Stardust encounter with comet 81P/Wild 2 [2] (i.e., normal incidence, 6 km s -1 ). We compare results of impact models, based on carefully defined particle structures, with three-dimensional (3D) crater shapes reported from Stardust [3,4]. This allows us to assess the extent to which particle construction is reflected in the resulting impact feature, and hence how we might infer impactor structure from crater shape. Our aim is to improve interpretation of Wild 2 dust characteristics, especially sub-grain dimensions, internal porosity and overall grain density. Here we present a simulation of a complex impact seen on Stardust foil C029W,1 [4], and show that a similar shape is consistent with the structure of a reasonably simple aggregate impactor model. Quantitative 3-D measurement of crater shape: Using MeX software, we produced detailed digital elevation models (DEMs) from stereo-pair scanning electron microscope (SEM) images, and quantified the depth and lateral dimensions [5]. Crater depth is influenced by a number of impactor characteristics, amongst which density is important [5]. DEMs for complex Stardust craters such as Fig. 1, reveal multiple depressions which have been interpreted as implying discrete concentrations of mass within a larger porous particle body [4], yielding very complex crater excavation. But just how realistic is the simplistic internal structural model (Fig. 2) proposed by [4] for this impactor?
منابع مشابه
Tof-sims Analysis of Residues of Projectiles Shot onto Stardust Aluminum
Introduction: The samples from the Stardust space probe will offer the first opportunity for analyzing cometary matter collected under controlled conditions together with contemporary interstellar dust particles [1, 2]. Moreover, Stardust is the first sample return mission ever that provides material from a known solar system object other than the moon. The primary goal after sample arrival is ...
متن کاملThe Open University ’ s repository of research publications and other research outputs Comet 81 P / Wild 2 : the size distribution of finer ( sub - 10 m ) dust collected by the Stardust spacecraft
The fluence of dust particles < 10 micrometres in diameter was recorded by impacts on aluminium foil of the NASA Stardust spacecraft during a close fly-by of comet 81P/Wild 2 in 2004. Initial interpretation of craters for impactor particle dimensions and mass was based upon laboratory experimental simulations using >10 μm diameter projectiles and the resulting linear relationship of projectile ...
متن کاملComet 81p/wild 2: the Size Distribution of Finer (sub 10- Micrometre) Dust Collected by the Stardust Spacecraft
The fluence of dust particles < 10 micrometres in diameter was recorded by impacts on aluminium foil of the NASA Stardust spacecraft during a close fly-by of comet 81P/Wild 2 in 2004. Initial interpretation of craters for impactor particle dimensions and mass was based upon laboratory experimental simulations using >10 μm diameter projectiles and the resulting linear relationship of projectile ...
متن کاملComet 81p/wild 2: the Updated Stardust Coma Dust Fluence Measurement for Smaller
Introduction: Micrometre and smaller scale dust within cometary comae can be observed by telescopic remote sensing spectroscopy [1] and the particle size and abundance can be measured by in situ spacecraft impact detectors [2]. Initial interpretation of the samples returned from comet 81P/Wild 2 by the Stardust spacecraft [3] appears to show that very fine dust contributes not only a small frac...
متن کامل