Stellar wind regimes of close-in extrasolar planets
Stellar wind regimes of close-in extrasolar planets
复制标题
近距离系外行星的恒星风状况
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
U. Motschmann
中科院分区：
文献类型：
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作者：
S. Preuße;A. Kopp;J. Büchner;U. Motschmann
类太阳恒星的近距系外行星所暴露于的恒星风条件与太阳系行星所面临的条件大不相同。不幸的是，这些恒星风属于这些行星系统中仍然未知的参数。另一方面，它们在许多可能导致可观测辐射事件的恒星 - 行星相互作用过程中起着至关重要的作用。为了给研究此类相互作用过程奠定基础，我们依据韦伯和戴维斯的太阳风模型估算恒星风参数，并研究恒星磁场的影响。我们的结果表明，与太阳系行星不同，一些近距系外行星可能是亚阿尔芬恒星风流中的障碍物。在这种情况下，恒星风的磁压与动压相当，甚至更大。我们讨论了这些发现对恒星风 - 系外行星相互作用可能产生的后果。此外，我们推导出了此类恒星风在系外行星磁层中所能沉积能量的上限估计值。最后，我们讨论了亚阿尔芬环境可能对恒星 - 行星相互作用产生的影响。
Close-in extrasolar planets of Sun-like stars are exposed to stellar wind conditions that differ considerably from those for planets in the solar system. Unfortunately, these stellar winds belong to the still unknown parameters of these planetary systems. On the other hand, they play a crucial role in a number of star-planet interaction processes that may lead to observable radiation events. In order to lay a foundation for the investigation of such interaction processes, we estimate stellar wind parameters on the basis of the solar wind model by Weber & Davis and study the implications of the stellar magnetic fields. Our results suggest that in contrast to the solar system planets, some close-in extrasolar planets may be obstacles in a sub- Alfvenic stellar wind flow. In this case, the stellar wind magnetic pressure is comparable to or even larger than the dynamic flow pressure. We discuss possible consequences of these findings for the wind-exoplanet interactions. Further, we derive upper limit estimates for the energies such stellar winds can deposit in the exoplanetary magnetospheres. We finally discuss the implications the sub-Alfvenic environment may have on the star-planet interaction.