Light Scattering by Aggregates with Sizes Comparable to the Wavelength: An Application to Cometary Dust

Optical properties of cometary dust

“…Previous attempts to model cometary dust properties were restricted to explaining only a part of these observational features (see, e.g., Mukai et al 1987;Mukai & Mukai 1990;Lumme & Rahola 1994;Xing & Hanner 1997;Yanamandra-Fisher & Hanner 1999;Petrova et al 2000;Kimura 2001). In this Letter, we report the first successful model that reproduces all the main light-scattering properties of cometary dust.…”

Interaction of particles in the near field and opposition effects in regolith-like surfaces

“…To illustrate this speculation, we present the polarization phase function obtained for randomly oriented clusters composed of 15 spheres in contact with size parameters ranging from approximately 1.0 to 1.6. We chose this range because the aggregates consisting of such monomers most often (depending on the refractive index and structure) show the negative branch of polarization (e.g., Petrova et al, 2000;2004 and references therein). The clusters were generated by the ballistic particle cluster aggregation method (Meakin 1983).…”

Inhomogeneous particle model for light-scattering by cometary dust

“…In light-scattering simulations, cometary dust particles are most often modelled as homogeneous aggregated structures (Lumme and Penttilä, 2011;Zubko et al, 2011;Shen et al, 2009;Kimura et al, 2006;Petrova et al, 2000;Xing and Hanner, 1997;Mukai et al, 1991), in which the refractive index is obtained using the effective-medium approximation or left as a free parameter. Homogenization of complex heterogeneous media with intrinsic microstructure is a sufficient approximation if the inclusions are uniformly distributed and small enough compared to the exciting wavelength.…”