Experimental characterization of the opposition surge in fine-grained water–ice and high albedo ice analogs

Jost, Bernhard; Pommerol, Antoine; Poch, Olivier; Gundlach, Bastian; Leboeuf, M.; Dadras, M.; Blum, Jürgen; Thomas, N.

doi:10.1016/j.icarus.2015.09.020

Cited by 26 publications

(33 citation statements)

References 73 publications

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“…This is probably due to the surface roughness of the samples made of spherical L and crushed L particles, higher by a factor of 4 to 5 compared to the surface made of spherical S particles, as measured by OCT (see Figures b, e, and h). This observation is consistent with the one of Jost et al () who observed that a rough surface of aluminum oxide particles shows a broader opposition peak than a flat surface at small incidence angles (see Figure 8 in Jost et al, ). The main parameter contributing to the width of the opposition peak thus seems to be the macroscopic surface roughness.…”

Section: Resultssupporting

confidence: 92%

“…At the University of Bern, we have developed a series of Setups for the Preparation of Icy Planetary Analogues (SPIPA) that are used to prepare spherical water ice particles, pure or mixed with contaminants, in a reproducible way. In previous works, we have measured their spectro‐photometric properties: phase curves and bidirectional reflectance distribution functions using the PHIRE‐2 instrument (Jost et al, ; Yoldi et al, ) and reflectance spectra using the SCITEAS setup (Poch et al, ). In the present study, we describe the first results of a new polarimetric setup developed in our group, called POLICES for POLarimeter for ICE Samples.…”

Section: Introductionmentioning

confidence: 99%

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Polarimetry of Water Ice Particles Providing Insights on Grain Size and Degree of Sintering on Icy Planetary Surfaces

et al. 2018

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The polarimetry of the light scattered by planetary surfaces is a powerful tool to provide constraints on their microstructure. To improve the interpretation of polarimetric data from icy surfaces, we have developed the POLarimeter for ICE Samples complementing the measurement facilities of the Ice Laboratory at the University of Bern. The new setup uses a high precision Stokes polarimeter to measure the degree of polarization in the visible light scattered by surfaces at moderate phase angles (from 1.5° to 30°). We present the photometric and polarimetric phase curves measured on various surfaces made of pure water ice particles having well‐controlled size and shape (spherical, crushed, and frost). The results show how the amplitude and the shape of the negative polarization branch change with the particles sizes and the degree of metamorphism of the ice. We found that fresh frost formed by water condensation on cold surfaces has a phase curve characterized by resonances (Mie oscillations) indicating that frost embryos are transparent micrometer‐sized particles with a narrow size distribution and spherical shape. Comparisons of these measurements with polarimetric observations of the icy satellites of the Solar System suggest that Europa is possibly covered by relatively coarser (~40–400 μm) and more sintered grains than Enceladus and Rhea, more likely covered by frost‐like particles of few micrometers in average. The great sensitivity of polarization to grain size and degree of sintering makes it an ideal tool to detect hints of ongoing processes on icy planetary surfaces, such as cryovolcanism.

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Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Polarimetry of Water Ice Particles Providing Insights on Grain Size and Degree of Sintering on Icy Planetary Surfaces

et al. 2018

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“…The measurements that are made in the opposition-effect region were carried out by Jost et al (2016) for icy particles with a high-albedo close to unity and by Psarev et al (2007) for low-and high-albedo samples. We found that the laboratory reflectance data from carbon soot at the wavelength of 630 nm in the phase angle range of 0.008…”

Section: Comparison With Laboratory Measurements Of the Phase Curve Amentioning

confidence: 99%

“…The OE parameters are the amplitude (also specified as the enhancement factor, ζ) and the angular width estimated as the half-width at half-maximum, HWHM. The effect has been observed on various planetary surfaces (Belskaya & Shevchenko 2000;Rosenbush et al 2002;Shevchenko et al 2008;Déau et al 2009) and planetary regolith analogs in the laboratory (Shkuratov et al 2002;Psarev et al 2007;Déau et al 2013;Jost et al 2016).…”

Section: Introductionmentioning

confidence: 97%

Opposition effect on comet 67P/Churyumov-Gerasimenko using Rosetta-OSIRIS images

Masoumzadeh

Oklay

Kolokolova

et al. 2017

A&A

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Aims. We aim to explore the behavior of the opposition effect as an important tool in optical remote sensing on the nucleus of comet 67P/ Churyumov-Gerasimenko (67P), using Rosetta-OSIRIS images acquired in different filters during the approach phase, July-August 2014 and the close flyby images on 14 of February 2015, which contain the spacecraft shadow. Methods. We based our investigation on the global and local brightness from the surface of 67P with respect to the phase angle, also known as phase curve. The local phase curve corresponds to a region that is located at the Imhotep-Ash boundary of 67P. Assuming that the region at the Imhotep-Ash boundary and the entire nucleus have similar albedo, we combined the global and local phase curves to study the opposition-surge morphology and constrain the structure and properties of 67P. The model parameters were furthermore compared with other bodies in the solar system and existing laboratory study. Results. We found that the morphological parameters of the opposition surge decrease monotonically with wavelength, whereas in the case of coherent backscattering this behavior should be the reverse. The results from comparative analysis place 67P in the same category as the two Mars satellites, Phobos and Deimos, which are notably different from all airless bodies in the solar system. The similarity between the surface phase function of 67P and a carbon soot sample at extremely small angles is identified, introducing regolith at the boundary of the Imhotep-Ash region of 67P as a very dark and fluffy layer.

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“…These droplets are conducted through a plastic tube inside a modified chest freezer cooled down to about 223 K and are then deposited onto an aluminum bowl in contact with a vessel containing liquid nitrogen [ Yoldi et al , ; Jost et al , ]. This technique produces quasi‐spherical ice particles with a mean diameter equal to 4.5 ± 2.5 μm (the second number is the standard deviation) as measured by cryo‐SEM (Scanning Electron Microscope) [see Jost et al , , Figure 5.a]. A second technique consists of using a peristaltic pump to conduct deionized water through a 2 mm diameter tube connected to a Hielscher 200Ht ultrasonic unit equipped with a S26d18S sonotrode.…”

Section: Samples Preparationmentioning

confidence: 99%

Characterization of the permittivity of controlled porous water ice-dust mixtures to support the radar exploration of icy bodies

Brouet

Neves

Sabouroux

et al. 2016

J. Geophys. Res. Planets

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The internal properties of porous and icy bodies in the solar system can be investigated by ground‐penetrating radars (GPRs), like the COmet Nucleus Sounding Experiment by Radiowave Transmission instrument on board the Rosetta spacecraft which has sounded the interior of the nucleus of comet 67P/Churyumov‐Gerasimenko. Accurate constraints on the permittivity of icy media are needed for the interpretation of the data. We report novel permittivity measurements performed on water ice samples and icy mixtures with porosities in the 31–91% range. The measurements have been performed between 50 MHz and 2 GHz with a coaxial cell on a total of 38 samples with a good reproducibility. We used controlled procedures to produce fine‐grained and coarse‐grained ice samples with a mean diameter of 4.5 μm and 67 μm, respectively, and to prepare icy mixtures. The JSC‐1A lunar regolith simulant was used as the dust component in the mixtures. The results are focused on the real‐part ε′ of the permittivity, which constrains the phase velocity of the radio waves in low‐loss media. The values of ε′ show a nondispersive behavior and are within the range of 1.1 to 2.7. They decrease with the increasing porosity Φ according to E(1 − Φ), with E equal to about 3.13 for pure water ice, and in the 3.8–7.5 range for ice‐dust mixtures with a dust‐to‐ice volumetric ratio in the 0.1–2.8 range, respectively. These measurements are also relevant for radiometers operating in the millimeter‐submillimeter domains, as suggested by the nondispersive behavior of the mixtures and of the pure components.

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Experimental characterization of the opposition surge in fine-grained water–ice and high albedo ice analogs

Cited by 26 publications

References 73 publications

Polarimetry of Water Ice Particles Providing Insights on Grain Size and Degree of Sintering on Icy Planetary Surfaces

Polarimetry of Water Ice Particles Providing Insights on Grain Size and Degree of Sintering on Icy Planetary Surfaces

Opposition effect on comet 67P/Churyumov-Gerasimenko using Rosetta-OSIRIS images

Characterization of the permittivity of controlled porous water ice-dust mixtures to support the radar exploration of icy bodies

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