Aerosol in the Martian atmosphere from KRFM experimental data

Preliminary analytical results of photometric limb-to-limb profiles of Mars obtained in eight narrow bands between 315 and 550 nm from the Phobos-2 spacecraft are presented in terms of the optical properties of the atmosphere and surface. The imaginary part of the refraction index is estimated for the 'constant' dust haze, using Mie theory for spherical particles. The index values are several times higher than those obtained by laboratory tests of analogous terrestrial materials, including basalt, andesite, and montmorillonite. The explanations proposed for this phenomenon are the influence of the irregular shape of the particles and/or the presence of some absorbing substance. Particle sizes a few tenths of a micron with a refraction index of 1.55 are compatible with the conventional 'constant' haze model.