On the possible changes in the physical characteristics of the aerosol in the deep layers of the atmosphere of Saturn

1Ovsak, AS
1Main Astronomical Observatory of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
Kinemat. fiz. nebesnyh tel (Online) 2019, 35(1):42-56
Start Page: Dynamics and Physics of Solar System Bodies
Language: Russian

This work is devoted to determining the values of the physical parameters of cloud particles in the deep layers of the Saturn's atmosphere using data from remote measurements of the solar radiation field diffusely reflected by a giant planet. In the previous study, using the effective optical depth method, from the spectral measurements of the geometric albedo of Saturn in 1993 in the wavelength range 300...1000 nm, the author obtained a pressure dependence, i. e. change with altitude in the atmosphere values of the magnitude of the aerosol scattering component of the optical depth. The analysis of the initial data was performed in the long-wave part of the spectrum in methane absorption lines of different power with centers at wavelengths of = 619, 727, 842, 864, and 887 nm. At certain altitude levels in the deep layers of the atmosphere of the giant planet, the indicated dependence shows features that possibly reflect changes of the physical characteristics of the aerosol. Therefore, the aim of this work was to determine the possible values of the physical parameters of aerosol particles in the deep layers of Saturn's atmosphere at altitudinal levels, with the features noted above. As a result, an increase in the effective radius of cloud particles was observed in the transition from the outer to the deeper layers of the atmosphere of giant planet: from the 1.4 μm in the upper part of the troposphere, to the 1.83 μm in the altitude region with a pressure of 1.0...1.25 bar and up to 2.2...2.4 μm in the region with a pressure of 1.5...2.0 bar. In the latter segment, a decrease in the real part of the refractive index of aerosol particles by 3.5 % was revealed. A possible reason for this decrease is the change in the phase state of aerosol particles in the lower and warmer atmospheric layers of Saturn, due to the presence of ammonium hydroxide in their composition in sufficient concentration.

Keywords: aerosol particles, atmosphere, deep layers, physical parameters, Saturn

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