The effect of star flare activity on the structure of the hydrogen-helium upper atmosphere of hot Jupiter

In the paper using 1D aeronomic model the impact of a stellar flare on the upper atmosphere of hot Jupiter is investigated. The atmosphere is assumed to have a hydrogen-helium chemical composition, and calculations were carried out for the hot Jupiter HD 209458b. We examined single and repeated flares in which the flux of hard UV radiation increases by 10, 100 and 1000 times compared to the quiescent state of the star. The active phase of the dynamic response of the atmosphere lasts 12–15 hours after the flare, and the characteristic period of relaxation to the initial state is about a day. From the results obtained it follows that the flare activity of solar-type stars does not have a significant effect on the evolution of the planetary atmospheres of hot Jupiters. However, the interpretation of transit observations of the disturbed atmospheres of hot Jupiters will make it possible to separate from each other the observational effects associated with the interaction of stellar flares and coronal mass ejections with the upper atmospheres and envelopes of these planets. This will make it possible to more accurately determine the parameters of the stellar wind and coronal mass ejections of solar-type parent stars.