On one effect of coronal mass ejections influence on the envelopes of hot Jupiters

TL;DR

This paper uses 3D MHD modeling to demonstrate how coronal mass ejections can cause the appearance and disappearance of bow shocks around hot Jupiters, affecting their observational signatures.

Contribution

It reveals a new effect where stellar wind fluctuations due to CMEs influence bow shock formation around hot Jupiters, confirmed through numerical simulations.

Findings

Coronal mass ejections can switch bow shock presence on hot Jupiters.

Stellar wind fluctuations affect hot Jupiter magnetosphere structure.

Observational luminosity can vary due to CME-induced bow shock changes.

Abstract

It is now established that the hot Jupiters have extensive gaseous (ionospheric) envelopes, which expanding far beyond the Roche lobe. The envelopes are weakly bound to the planet and affected by strong influence of stellar wind fluctuations. Also, the hot Jupiters are located close to the parent star and therefore the magnetic field of stellar wind is an important factor, determining the structure their magnetosphere. At the same time, for a typical hot Jupiter, the velocity of stellar wind plasma, flowing around the atmosphere, is close to the Alfv\'en velocity. This should result in stellar wind parameters fluctuations (density, velocity, magnetic field), that can affect the conditions of formation of bow shock waves around a hot Jupiter, i. e. to switch flow from sub-Alfv\'en to super-Alfv\'en mode and back. In this paper, based on the results of three-dimensional numerical MHD modeling, it is confirmed that in the envelope of hot Jupiter, which is in Alfv\'en point vicinity of the stellar wind, both disappearance and appearance of the bow shock wave occures under the action of coronal mass ejection. The paper also shows that this effect can influence the observational manifestations of hot Jupiter, including luminosity in energetic part of the spectrum.