Published online by Cambridge University Press: 27 February 2018
The evolution of the polarization of light scattered by dust particles (e.g. cometary dust) with the phase angle is an indicator of the physical properties of the particles. For grains large compared to the wavelength, the maximum value of polarization Pmax increases with increasing size. A dichotomy is pointed out in the cometary poiarimetric phase curves, showing two ranges of values for Pmax. A comparison between laboratory measurements performed under Earth and microgravity conditions is presented. Pmax and the corresponding αmax appear to be smaller in microgravity than for ground based measurements. The comparison between ground based, microgravity and cometary results is then tentatively discussed in term of physical properties of the grains.