[en] The thermal model of the cometary nucleus on the basis of numerical solution of nonstationary heat conduction equation with regard to the energy balance on the surface, variability of thermophysical characteristics of material, influence of the dust component, proper rotation and orbital motion of a comet is considered. Temperature fields are calculated; the value of the reaction force, arising on the anisotropic gas flow out of the nucleus are estimated. The photometric model of the area around the nucleus containing quantitative estimations of the optic properties of the nucleus and dusty-gas atmosphere is constructed, with the application of the thermal model characteristics. The problem of brightness distribution in the surrounding of the cometary nucleus is investigated qualitatively

[en] A thermal model of a cometary nucleus is analyzed on the basis of a numerical solution of the nonsteady heat-conduction equation with allowance for energy balance at the surface, variability of the thermophysical characteristics of the material, the influence of the dust component, and the proper rotation and orbital motion of the comet. The temperature fields are calculated and the reactive force generated in the anisotropic outflow of volatile components of the nucleus is estimated. Using the characteristics of the thermal model, a photometric model of the region near the nucleus is constructed, containing quantitative estimates of the optical properties of the nucleus and the gas - dust atmosphere. The problem of the brightness distribution in the vicinity of a cometary nucleus is investigated qualitatively