Shalygina O. Properties of stratospheric aerosol in polar regions of Jupiter on the base of photopolarimetric observations.

In the dissertation physical conditions in the upper atmosphere of Jupiter and properties of aerosol in the polar areas of the planet were studied. The work is based on the data of groud-based photopolarimetric observations of Jupiter and on the elements of theory of forming of aerosols. Polarimetric database created by the author on the base of own observations and the data of other researchers, was analysed in the work. This database describes behaviour of Jupiter's polarization during 48 years and it has not the analogues in the world. On the basis of this information, inverse dependence of the parameter of asymmetry of linear polarization on insolation was found: polarization is higher in colder hemisphere, which is ascribed to increasing concentration of aerosol haze. Explanation of the origin of considerable linear polarization in the polar areas of Jupiter at zero phase angle has been proposed. Light from underlaying surface (clouds) scattered by the layer of stratosphere aerosol haze is shown to give considerable contribution in the polarization. Seasonal fluctuations of temperature in the stratosphere of Jupiter are shown to control formation the polar aerosol haze that consists most probably of solid particles of polycyclic aromatic hydrocarbons (naphthalene, phenanthrene). This can explain the seasonal changes of polarization in the polar areas of Jupiter. The possibility of influence of solar cosmic rays (high-energy particles) on formation of polar haze on Jupiter is pointed out.