PROGRA2 experiment: New results for dust clouds and regoliths analogs

Hadamcik, Edith; Renard, Jean‐Baptiste; Levasseur-Regourd, Anny Chantal; Worms, Jean-Claude

doi:10.1016/j.asr.2005.06.019

Cited by 8 publications

(2 citation statements)

References 21 publications

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“…Monte-Carlo techniques have been recently developed by Muinonen [47] to take into account the multiple scattering, with both coherent backscattering and radiative transfer theories, for semi-infinite plane-parallel media of spherical monodisperse scatterers with various size parameters. They are being compared with laboratory measurements on highly porous 'cakes' of silica spheres [48].…”

Section: Interpretation Through Simulations Of Light Scattering Obser...mentioning

confidence: 99%

NEO sizes, shapes and surface physical properties

Levasseur-Regourd¹,

Fulchignoni²,

Delbò³

et al. 2005

Comptes Rendus. Physique

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The sizes, shapes, and surface or subsurface properties of Near Earth Objects (mostly asteroids, also inactive comet nuclei) are still poorly known, since any accurate determination requires in situ missions. It may nevertheless be estimated that the sizes of these irregular bodies range from a few tens of kilometres to a few tens of meters, with possibly about 1000 NEOs with sizes greater than 1 km. Their surfaces are estimated to be quite rough, and at least partially covered with regolith.

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Section: Interpretation Through Simulations Of Light Scattering Obser...mentioning

confidence: 99%

NEO sizes, shapes and surface physical properties

Levasseur-Regourd¹,

Fulchignoni²,

Delbò³

et al. 2005

Comptes Rendus. Physique

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“…The first samples from the lunar surface returned by Apollo 11 showed a striking resemblance with the selected material (Dollfus 1998), thus validating the technique. Numerous other works have generally focused on inferring the properties of particulate surfaces through the characteristics of their observed polarization phase-curves; Geake & Geake (1990) and Kolokolova et al (1993) studied how the polarization-phase curve of powder surfaces varies in scale and shape with grain size for sub-wavelength grains; Shkuratov et al (2002Shkuratov et al ( , 2007a measured the scattering by particulate surfaces of various compositions and focused on the origin of the opposition effect and negative branches of the phase curve; Lasue et al (2006) and Hadamcik et al (2003Hadamcik et al ( , 2006 modeled cometary light observations by the light scattered by porous irregular aggregates of submicron grain sizes of silica and organics.…”

Section: It Obscured Your Vision If You Let It Get On Your Visor It mentioning

confidence: 99%

Lunar dust characterization by polarimetric signature

Richard¹,

Davis²

2008

A&A

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Context. In support of NASA's exploration program and the return to the Moon, the polarimetric signature of dispersed individual Lunar regolith dust grains is studied to enable the characterization of the dust exopsheric environment by remote, in-situ, and standoff sensing. Aims. We explore the value of the negative polarization branch (NPB) as a signature for characterizing individual grains to determine if it can be used in the same way as for surfaces of planets and atmosphereless bodies. Methods. The linear polarization phase curve for single spheres of silicate and for aggregates of spherical silicate grains of different porosity are computed using the discrete dipole approximation (DDA) for a range of grain sizes. Features in these curves are identified and their evolution explored as a function of grain size and aggregate porosity. We focus particularly on the so-called negative polarization branch that has been historically used to characterize planetary surfaces. Results. Calculations show that polarization phase curves for spherical grains exhibit a sharp transition over a narrow range of size parameter between two distinct regimes, one typical of Rayleigh scattering and another dominated by a large NPB. The linear polarimetric signature observed for aggregates is a composite of a) the polarization induced by individual grains composing the aggregate and b) the polarization due to the aggregate as a whole dust grain. The weight of each component varies depending on the porosity of the aggregate. An NPB similar to the one observed for atmosphereless astronomical bodies is present for different ranges of the size parameter depending on the value of the porosity. It appears as a remnant of the negative branch exhibited by the single spherical grains. The sharper, narrow negative branch that is measured for some granular surfaces in the laboratory or seen in astronomical observations is not observed here. Conclusions. These results suggest that the wide negative branch is due to the scattering by individual grains and single aggregates, while the narrow negative branch is more likely due to coherent backscattering or shadowing effects in bulk material. The shape and evolution of the NPB could be used to characterize spherical grains and to differentiate between aggregates with the same porosity but different sizes, but does not appear to be a practical candidate for univocally differentiating between aggregates of different porosity.

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