Modelling of Polarization Properties of Cometary Dust Grains
  Observational data for dusty comets are summarized and systemized.   The dependence of the linear polarization on various parameters (the phase angle, wavelength, etc.) is analyzed. An ensemble of aligned spheroidal particles having various sizes and chemical compositions is used to fit the linear and circular polarization observed for the comet Halley. 
D.A. Semenov and N.V. Voshchinnikov (Astronomy Department and Sobolev   Astronomical Institute, St. Petersburg University)