arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1003.3838astro-ph.EP
收藏

热木星大气风的磁阻力

Magnetic Drag on Hot Jupiter Atmospheric Winds

Rosalba Perna, Kristen Menou, Emily Rauscher

摘要:

大气温度T ~ 1000 K的热电离层具有足够的残余热电离水平,使离子与行星磁场相互作用,从而对(中性)大气风产生相当大的磁阻力。我们评估了热木星HD 209458 b的代表性三维大气模型中磁阻力的大小,发现在这类大气中限制风速是一种合理的机制。磁阻力有很强的几何依赖性,无论是从白天到黑夜(在高层大气中),这可能会有有趣的后果,大气流动模式。推而广之,具有瞬时加热大气层的近距离偏心行星将经历随时间变化的磁阻力水平。热大气环流模型中磁阻力的稳健处理可能需要迭代求解磁感应和Saha方程,因为流体动力学流动正在演变。

英文摘要:

Hot Jupiters, with atmospheric temperatures T ~ 1000 K, have residual thermal ionization levels sufficient for the interaction of the ions with the planetary magnetic field to result in a sizable magnetic drag on the (neutral) atmospheric winds. We evaluate the magnitude of magnetic drag in a representative three-dimensional atmospheric model of the hot Jupiter HD 209458b and find that it is a plausible mechanism to limit wind speeds in this class of atmospheres. Magnetic drag has a strong geometrical dependence, both meridionally and from the day to the night side (in the upper atmosphere), which could have interesting consequences for the atmospheric flow pattern. By extension, close-in eccentric planets with transiently heated atmospheres will experience time-variable levels of magnetic drag. A robust treatment of magnetic drag in circulation models for hot atmospheres may require iterated solutions to the magnetic induction and Saha equations as the hydrodynamical flow is evolved.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑