Multi-Component MHD Model of Hot Jupiter Envelopes

Abstract

A numerical model description of a hot Jupiter extended envelope based on the approximation of multi-component magnetic hydrodynamics is presented. The main attention is focused on the problem of implementing the completed MHD stellar wind model. As a result, the numerical model becomes applicable for calculating the structure of the extended envelope of hot Jupiters not only in the super-Alfvén and sub-Alfvén regimes of the stellar wind flow around and in the trans-Alfvén regime. The multi-component MHD approximation allows the consideration of changes in the chemical composition of hydrogen–helium envelopes of hot Jupiters. The results of calculations show that, in the case of a super-Alfvén flow regime, all the previously discovered types of extended gas-dynamic envelopes are realized in the new numerical model. With an increase in magnitude of the wind magnetic field, the extended envelope tends to become more closed. Under the influence of a strong magnetic field of the stellar wind, the envelope matter does not move along the ballistic trajectory but along the magnetic field lines of the wind toward the host star. This corresponds to an additional (sub-Alfvénic) envelope type of hot Jupiters, which has specific observational features. In the transient (trans-Alfvén) mode, a bow shock wave has a fragmentary nature. In the fully sub-Alfvén regime, the bow shock wave is not formed, and the flow structure is shock-less.

The Kinetic Monte Carlo Model of the Auroral Electron Precipitation into N2-O2 Planetary Atmospheres

“…The chemistry and dynamics of NO in N 2 -O 2 atmospheres of hot sub-neptunes and exo-earths will be studied using the current and earlier developed kinetic Monte Carlo models [64][65][66], designed to investigate the kinetics and transport of suprathermal particles in planetary atmospheres. In addition, in our future studies, the recently developed multi-component MHD model [67] will be used to calculate the effect of the stellar wind on the process of destruction of nitric oxide and the removal of NO from the upper atmosphere by the polar wind. Finally, this will allow us to calculate the distribution of nitric oxide NO in the upper atmosphere of the terrestrial-type exoplanet depending on the activity level of the host star and to assess the possibility of observing this potential atmospheric biomarker.…”

Multi-component MHD model for hydrogen-helium extended envelope of hot Jupiter

“…Magnetic field can play an important role in the process of the stellar wind flow around the atmosphere of the HJ. Therefore, we use MHD solution instead of hydrodynamic one for simulation (Zhilkin & Bisikalo 2021). In order to describe specific processes that lead to local changes in the concentration of components we take into account the chemical composition.…”

Editorial to the Special Issue “Advances in the Physics of Stars—In Memory of Prof. Yuri N. Gnedin”

“…In the article [8], the multi-component numerical model of hot Jupiter envelopes is suggested. By implementing the completed magnetohydrodynamic model of stellar wind, it becomes possible to calculate the structure of an extended envelope of hot Jupiter in both the super-Alfvén and sub-Alfvén regimes of the stellar wind flow as well in the trans-Alfvén regime.…”