Scattering of light by a large, densely packed agglomerate of small silica spheres.

We model the measured phase function and degree of linear polarization of a macroscopic agglomerate made of micrometer-scale silica spheres using the methodology of multiple scattering. In the laboratory work, the agglomerate is produced ballistically, characterized by scanning electron microscopy, and measured with the $ {\text{PROGRA}^{2}} $PROGRA instrument to obtain the light scattering properties. The model phase function and degree of polarization are in satisfactory agreement with the experimental data.

The 67P/Churyumov-Gerasimenko observation campaign in support of the Rosetta mission.

We present a summary of the campaign of remote observations that supported the European Space Agency's Rosetta mission. Telescopes across the globe (and in space) followed comet 67P/Churyumov-Gerasimenko from before Rosetta's arrival until nearly the end of the mission in September 2016. These provided essential data for mission planning, large-scale context information for the coma and tails beyond the spacecraft and a way to directly compare 67P with other comets.

Scattering properties of sands. 2. Results for sands from different origins.

Mineral sand is a major component of aerosols in the atmosphere. It is necessary to have a laboratory database to interpret the remote sensing measurements of light scattered by such grains. For this purpose, the PROGRA2 experiment is dedicated to the retrieval of polarization and brightness phase curves, in the visible wavelength domain, of various grains that can be found in Earth's atmosphere and in space.

Chemical characterization of Titan's tholins: solubility, morphology and molecular structure revisited.

In this work Titan's atmospheric chemistry is simulated using a capacitively coupled plasma radio frequency discharge in a N(2)-CH(4) stationnary flux. Samples of Titan's tholins are produced in gaseous mixtures containing either 2 or 10% methane before the plasma discharge, covering the methane concentration range measured in Titan's atmosphere. We study their solubility and associated morphology, their infrared spectroscopy signature and the mass distribution of the soluble fraction by mass spectrometry.

Ultraviolet-visible bulk optical properties of randomly distributed soot.

The presence of soot in the lower stratosphere was recently established by in situ measurements. To isolate their contribution to optical measurements from that of background aerosol, the soot's bulk optical properties must be determined. Laboratory measurements of extinction and polarization of randomly distributed soot were conducted.