Numerical modeling results of interactions of the planetary atmosphere of Gliese 436b with ionizing radiation and the plasma wind of an M star are presented. A self-consistent gas-dynamic 2D model characterizing the processes of radiation heating and ionization and hydrogen photochemistry reactions was used in the modeling. It is demonstrated that Gliese 436b should have an extended (several tens of planetary radii) exosphere, which is formed by partially ionized gas with added molecular components, with a supersonic outflow velocity. The influence of such factors as the XUV radiation intensity and the temperature of the lower atmosphere on the mass loss rate is examined.
相似文献Results of a study of the influence of solar-type host stars superflares on the gas dynamics of the extended envelopes of giant exoplanets are presented. During flare events, the radiation intensity of the host star in the extreme ultraviolet and soft X-ray can increase by several orders of magnitude for a short time, leading to strong local heating of the exoplanet atmosphere on the side facing the star, with the formation of shocks in the atmosphere. Computations of the gas-dynamical response of the atmosphere of the hot Jupiter HD 209458b to characteristic superflares of solar-like stars were carried out earlier in [1] using a one-dimensional aeronomical model correctly taking into account heating and chemical processes in the atmosphere. To investigate the outflow of atmospheric gas, the results obtained with this onedimensional model were used as simple boundary conditions for computations of the three-dimensional flow structure after a flare. The results of these three-dimensional gas-dynamical computations show that the mass ejection of the flare increases the size of the envelope over several hours, which could be detected with existing observing facilities. It is shown that the mass-loss rates for the most powerful superflare considered could be enhanced by an order of magnitude over several tens of hours after the flare.
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