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首页> 外文期刊>The Astrophysical journal >MAGNETOSPHERES OF “HOT JUPITERS”: THE IMPORTANCE OF MAGNETODISKS IN SHAPING A MAGNETOSPHERIC OBSTACLE
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MAGNETOSPHERES OF “HOT JUPITERS”: THE IMPORTANCE OF MAGNETODISKS IN SHAPING A MAGNETOSPHERIC OBSTACLE

机译:“热小行星”的磁球:磁碟在塑造磁球障碍中的重要性

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摘要

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 atmosphere mass loss. The present work provides a more 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.
机译:潮汐锁定近距离巨型系外行星(“热木星”)的弱本征磁偶极矩在先前的研究中已显示出无法为其扩展的高层大气提供有效的磁层保护,以抵抗恒星等离子体流,这应导致非热大气质量损失。本工作基于抛物面磁层模型(PMM)提供了“热木星”磁层结构的更完整视图。除固有的行星磁偶极子外,PMM还考虑了主要磁场源中磁尾的电流系统,绝磁电流和磁盘的环形电流。由于从流体动力学扩展的高层大气中流出的离子化粒子,“热木星”可能具有扩展的磁盘。由磁盘磁环电流产生的磁场在“热木星”的固有磁偶极子的贡献之上占主导地位,并最终决定了整个磁层的大小和形状。磁场随距离的减小比偶极子减小的速度慢,形成了“热木星”磁磁盘为主的磁层的基本特征。与仅考虑行星偶极子的传统估计相比,这导致它们的比例大40%-70%。因此,磁盘的形成必须包括在恒星风等离子体与近地系外行星相互作用的研究中,以及对行星大气的磁层保护,以防止由于恒星等离子体流的侵蚀而引起的非热逸出。

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