LAUSR

Most hot Jupiters have extended envelopes of gas that spread beyond their Roche lobes. A typical envelope is weakly gravitationally bound to the planet and, therefore, its structure and properties are strongly affected by stellar wind disturbances, for example, coronal mass ejections. Earlier, we performed gas-dynamic modeling of the interaction of a narrow coronal mass ejection (CME) with the envelope of the hot Jupiter HD 209458b. In this study, we investigate the influence of the planet’s magnetic field and stellar wind on the structure and dynamics of the HD 209458b envelope exposed to a similar CME. For this, an MHD model of the CME interaction with the envelope was developed. It was assumed that the field of the planet had a generally accepted value and corresponded to 1/10 of the magnetic moment of Jupiter. The field of the star was assumed to be weak (10–3 G), which ensured the super-Alfven flow of the stellar wind around the planet. The comparison of the MHD simulation with gas-dynamic calculations shows that, for the adopted values of the fields of the planet and the star, the effect of the magnetic field on the envelope is not decisive and the qualitative picture of the flow does not change. At the same time, taking magnetic fields into account leads to a change in the quantitative characteristics of the envelope and the mass loss rate, which can be important in determining the evolutionary status of the exoplanet.