Magnetospheres of “Hot Jupiters”: The importance of magnetodisks in shaping a magnetospheric obstacleстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:Weak intrinsic magnetic dipole moments of tidally locked close-in giant exoplanets (“hot Jupiters”) have been shown in previous studies to be unable to provide an efficient magnetospheric protection for their expanding upper atmospheres against the stellar plasma flow, which should lead to significant non-thermal atmospheremass loss. The present work provides amore complete view of the magnetosphere structure of “hot Jupiters,” based on a paraboloid magnetospheric model (PMM). Besides the intrinsic planetary magnetic dipole, the PMM considers among the main magnetic field sources also the electric current system of the magnetotail, magnetopause currents, and the ring current of a magnetodisk. Due to the outflow of ionized particles from the hydrodynamically expanding upper atmosphere, “hot Jupiters” may have extended magnetodisks. The magnetic field produced by magnetodisk ring
currents dominates above the contribution of an intrinsic magnetic dipole of a “hot Jupiter” and finally determines the size and shape of the whole magnetosphere. A slower-than-the-dipole-type decrease of the magnetic field with the distance forms the essential specifics of magnetodisk-dominated magnetospheres of “hot Jupiters.” This results in their 40%–70% larger scales compared to those traditionally estimated by only the planetary dipole
taken into account. Therefore, the formation of magnetodisks has to be included in the studies of the stellar wind plasma interaction with close-in exoplanets, as well as magnetospheric protection for planetary atmospheres against non-thermal escape due to erosion by the stellar plasma flow.