Approaching interplanetary dust physical properties from light scattering and thermal observations and simulations

Physical properties of the interplanetary dust such as the local polarization and temperature, together with their heliocentric variations, may be derived from scattered and emitted light observations. With a realistic size distribution typical of the interplanetary dust, a very good fit of the polarization phase curve near 1 AU is obtained for a mixture of silicate and more absorbing organic material (approx 40 % in mass). The decrease of P_{90 deg} values with the solar distance is interpreted as a decrease of the organic percentage towards the Sun. Finally the contribution of dust particles of cometary origin is at least 20% at 1AU